feat(verfahrensablauf): URL state hybrid — filter chips in URL, scenario in localStorage (t-paliad-308, m/paliad#137)

Splits /tools/verfahrensablauf persisted state into two namespaces:

URL params (timeline kind — paste-able, shareable, refresh-resistant):
  proceeding, side, target, trigger_date

localStorage `paliad.verfahrensablauf.scenario.*` (per-user tweaks
that should never leak into a shared link):
  event_choices, court_id, ccr, inf_amend, rev_amend, rev_cci,
  show_hidden

Hydration order: URL wins. localStorage fills the rest. A shared link
reproduces the timeline kind but each user sees their own scenario
state.

Added trigger_date and proceeding to URL (previously DOM-only — a
refresh lost the date and the proceeding tile). Moved event_choices
and show_hidden from URL to localStorage (verbose, per-user). Added
court_id + flag persistence to localStorage (previously DOM-only).

New pure module `views/verfahrensablauf-state.ts` owns the URL +
localStorage contract: URL parsers + encoder (`applyFiltersToSearch`),
scenario read/write helpers, and a `hydrate()` orchestrator that
documents the URL→localStorage order. 31 unit tests pin the contract,
including the "shared link doesn't leak scenario state" invariant.

Anti-patterns explicitly avoided:
- No ?appellant= resurrection (#132 removed it; engine reads from
  the single side picker for role-swap proceedings).
- trigger_date in URL not localStorage (a shared link must reproduce
  the same dated timeline).
- URL→localStorage hydration order is contract; localStorage never
  overrides an explicit URL value.

Project-driven side-fill chip (?project=<id>) still overrides as
before — parseSideFromSearch is called before the project's our_side
is applied so an explicit ?side= still wins.

Build clean: `bun run build`, `bun test` (240 pass / 594 expect calls),
`go test ./...`, `go vet ./...`.

cmd/server/main.go

@@ -12,6 +12,7 @@ import (
 	"strconv"
 	"strings"
 	"syscall"
+	"time"
 
 	// Embed Go's IANA tz database into the binary so time.LoadLocation works
 	// without OS tzdata. The runtime image (alpine) doesn't ship /usr/share/
@@ -339,11 +340,13 @@ func main() {
 			log.Printf("CalDAV start: %v", err)
 		}
 		reminderSvc.Start(bgCtx)
-		// Slice B.4 (mig 140, t-paliad-305): legacy paliad.deadline_rules
-		// dropped. The B.2 dual-write drift-check loop is retired — the
-		// procedural_events / sequencing_rules / legal_sources tables
-		// are now the source of truth and there is no parallel side to
-		// compare against. Pre-drop drift was verified clean in mig 140.
+		// Slice B.2 dual-write drift check (t-paliad-305 / m/paliad#93).
+		// Runs every 6 h while the new procedural_events / sequencing_rules /
+		// legal_sources tables shadow the legacy paliad.deadline_rules
+		// table. A clean run logs at INFO; drift logs at WARN with the
+		// full report so a broken dual-write surfaces before the next
+		// deploy.
+		services.StartDualWriteDriftCheckLoop(bgCtx, pool, 6*time.Hour)
 		go func() {
 			<-bgCtx.Done()
 			log.Println("background services: shutdown signal received")

frontend/src/client/verfahrensablauf.ts

@@ -12,7 +12,6 @@ import { initI18n, t, tDyn, getLang, onLangChange } from "./i18n";
 import { initSidebar } from "./sidebar";
 import {
   type DeadlineResponse,
-  type Side,
   calculateDeadlines,
   escHtml,
   formatDate,
@@ -24,10 +23,27 @@ import {
 import {
   attachEventCardChoices,
   reseedChips,
-  currentChoices,
   type EventChoice,
-  type ChoiceKind,
 } from "./views/event-card-choices";
+import {
+  APPEAL_TARGETS,
+  SCENARIO_KEYS,
+  type AppealTarget,
+  type Side,
+  type StorageLike,
+  applyFiltersToSearch,
+  makeMemoryStorage,
+  parseAppealTargetFromSearch,
+  parseProceedingFromSearch,
+  parseSideFromSearch,
+  parseTriggerDateFromSearch,
+  readBoolFlag,
+  readCourtId,
+  readEventChoices,
+  writeBoolFlag,
+  writeCourtId,
+  writeEventChoices,
+} from "./views/verfahrensablauf-state";
 
 let selectedType = "";
 let lastResponse: DeadlineResponse | null = null;
@@ -119,21 +135,13 @@ const ROLE_LABELS: Record<string, RoleLabels> = {
 // Proceedings that surface the appeal-target chip group. Currently
 // only the unified upc.apl proceeding; future variants (e.g. de.apl)
 // can opt in by adding the code here.
+//
+// APPEAL_TARGETS itself lives in ./views/verfahrensablauf-state so the
+// pure URL parser and this page share the same canonical list.
 const APPEAL_TARGET_PROCEEDINGS = new Set([
   "upc.apl.unified",
 ]);
 
-// Five canonical appeal-target slugs (lp.AppealTargets — keep ordered
-// in sync with pkg/litigationplanner/types.go AppealTargets).
-const APPEAL_TARGETS = [
-  "endentscheidung",
-  "kostenentscheidung",
-  "anordnung",
-  "schadensbemessung",
-  "bucheinsicht",
-] as const;
-type AppealTarget = (typeof APPEAL_TARGETS)[number] | "";
-
 function hasAppealTarget(proceedingType: string): boolean {
   return APPEAL_TARGET_PROCEEDINGS.has(proceedingType);
 }
@@ -142,16 +150,35 @@ function hasAppellantAxis(proceedingType: string): boolean {
   return APPELLANT_AXIS_PROCEEDINGS.has(proceedingType);
 }
 
-function readSideFromURL(): Side {
-  const raw = new URLSearchParams(window.location.search).get("side");
-  return raw === "claimant" || raw === "defendant" ? raw : null;
+// Scenario storage — real localStorage in the browser, in-memory
+// fallback when localStorage throws (private mode, disabled storage,
+// etc.). All scenario writes go through this single handle so a
+// failure mode is isolated to one try/catch path.
+const scenarioStorage: StorageLike = makeScenarioStorage();
+
+function makeScenarioStorage(): StorageLike {
+  try {
+    const probe = "__paliad_va_probe__";
+    window.localStorage.setItem(probe, "1");
+    window.localStorage.removeItem(probe);
+    return window.localStorage;
+  } catch {
+    return makeMemoryStorage();
+  }
 }
 
-function writeSideToURL(s: Side) {
+// URL writers — all four chip params route through this single helper
+// so the canonical query-string shape (no empty values, no trailing
+// `?`) is enforced in one place.
+function applyURLFilters(filters: {
+  proceeding?: string;
+  side?: Side;
+  target?: AppealTarget;
+  triggerDate?: string;
+}): void {
   const url = new URL(window.location.href);
-  if (s === null) url.searchParams.delete("side");
-  else url.searchParams.set("side", s);
-  window.history.replaceState(null, "", url.pathname + (url.search ? url.search : "") + url.hash);
+  const nextSearch = applyFiltersToSearch(url.search, filters);
+  window.history.replaceState(null, "", url.pathname + nextSearch + url.hash);
 }
 
 // t-paliad-301 / m/paliad#132: applies ROLE_LABELS to the side-row
@@ -181,26 +208,6 @@ function applyRoleLabels(proceedingType: string) {
   }
 }
 
-// Slice B1 — appeal-target URL state. Empty string = no target picked
-// (the row is hidden because the proceeding isn't an appeal). Any
-// other value must be one of APPEAL_TARGETS; unknown values are
-// rejected by readAppealTargetFromURL so a stale link can't break
-// the engine filter.
-function readAppealTargetFromURL(): AppealTarget {
-  const raw = new URLSearchParams(window.location.search).get("target") || "";
-  if ((APPEAL_TARGETS as readonly string[]).includes(raw)) {
-    return raw as AppealTarget;
-  }
-  return "";
-}
-
-function writeAppealTargetToURL(t: AppealTarget) {
-  const url = new URL(window.location.href);
-  if (t === "") url.searchParams.delete("target");
-  else url.searchParams.set("target", t);
-  window.history.replaceState(null, "", url.pathname + (url.search ? url.search : "") + url.hash);
-}
-
 // Default target on first picker entry into upc.apl. m: Endentscheidung
 // is the most-common appeal target; the chip group also defaults
 // "Endentscheidung" checked in verfahrensablauf.tsx. Keep these two in
@@ -217,54 +224,18 @@ const anchorOverrides = new Map<string, string>();
 function clearAnchorOverrides() { anchorOverrides.clear(); }
 
 // Per-event-card choices (t-paliad-265). Unbound on this page (no
-// project context), so persistence is URL-only via `?event_choices=`.
-// Format: comma-separated `submission_code:kind=value` tuples. Same
-// idiom as `?side=` + `?appellant=`.
-let perCardChoices: EventChoice[] = [];
+// project context). Persistence moved from URL → localStorage under
+// SCENARIO_KEYS.eventChoices (t-paliad-308 / m/paliad#137) — these
+// are per-user scenario tweaks, not the timeline kind, so a shared
+// link should NOT leak them into the recipient's view.
+let perCardChoices: EventChoice[] = readEventChoices(scenarioStorage);
 
-function readChoicesFromURL(): EventChoice[] {
-  const raw = new URLSearchParams(window.location.search).get("event_choices");
-  if (!raw) return [];
-  const out: EventChoice[] = [];
-  for (const tuple of raw.split(",")) {
-    const m = tuple.match(/^([^:]+):([^=]+)=(.+)$/);
-    if (!m) continue;
-    const kind = m[2] as ChoiceKind;
-    if (kind !== "appellant" && kind !== "include_ccr" && kind !== "skip") continue;
-    out.push({ submission_code: m[1], choice_kind: kind, choice_value: m[3] });
-  }
-  return out;
-}
-
-function writeChoicesToURL(choices: EventChoice[]) {
-  const url = new URL(window.location.href);
-  if (choices.length === 0) {
-    url.searchParams.delete("event_choices");
-  } else {
-    const enc = choices.map((c) => `${c.submission_code}:${c.choice_kind}=${c.choice_value}`).join(",");
-    url.searchParams.set("event_choices", enc);
-  }
-  window.history.replaceState(null, "", url.pathname + (url.search ? url.search : "") + url.hash);
-}
-
-// Show-hidden toggle state (t-paliad-290 / m/paliad#122). When ON, the
+// Show-hidden toggle (t-paliad-290 / m/paliad#122). When ON, the
 // calculator re-surfaces cards whose submission_code is in the active
 // skipRules set; they render faded with a "Wieder einblenden" chip.
-// URL-driven via ?show_hidden=1 so a shared link or reload preserves
-// the visibility. Default OFF — m's not asking to see hidden by
-// default, just to be able to.
-function readShowHiddenFromURL(): boolean {
-  return new URLSearchParams(window.location.search).get("show_hidden") === "1";
-}
-
-function writeShowHiddenToURL(on: boolean) {
-  const url = new URL(window.location.href);
-  if (on) url.searchParams.set("show_hidden", "1");
-  else url.searchParams.delete("show_hidden");
-  window.history.replaceState(null, "", url.pathname + (url.search ? url.search : "") + url.hash);
-}
-
-let showHidden = readShowHiddenFromURL();
+// Persistence moved from URL → localStorage (t-paliad-308) — it's a
+// per-user UX preference, not scenario state worth sharing in a link.
+let showHidden = readBoolFlag(scenarioStorage, SCENARIO_KEYS.showHidden);
 
 type ProcedureView = "timeline" | "columns";
 let procedureView: ProcedureView = "columns";
@@ -568,7 +539,7 @@ function syncInfAmendEnabled() {
   if (!ccr.checked) infAmend.checked = false;
 }
 
-function selectProceeding(btn: HTMLButtonElement) {
+function selectProceeding(btn: HTMLButtonElement, opts: { writeURL?: boolean } = {}) {
   document.querySelectorAll(".proceeding-btn").forEach((b) => b.classList.remove("active"));
   btn.classList.add("active");
   const nextType = btn.dataset.code || "";
@@ -578,20 +549,76 @@ function selectProceeding(btn: HTMLButtonElement) {
   if (selectedType !== nextType) clearAnchorOverrides();
   selectedType = nextType;
 
+  // Persist the picked proceeding to ?proceeding= so a refresh / shared
+  // link reproduces the same tile. writeURL=false on the load-time
+  // hydration path so we don't churn history.replaceState when the
+  // URL already carries the canonical value.
+  if (opts.writeURL !== false) {
+    applyURLFilters({ proceeding: selectedType });
+  }
+
   // Trigger-event label fires from the calc response (root rule).
   // Until step 3 renders, fall back to an em-dash placeholder.
   lastResponse = null;
   syncTriggerEventLabel();
 
-  void populateCourtPicker("court-picker-row", "court-picker", selectedType);
   syncFlagRows();
   syncAppealTargetRowVisibility();
   applyRoleLabels(selectedType);
+  // Restore flags from localStorage BEFORE the initial calc so the
+  // first /api/tools/fristenrechner POST already carries the user's
+  // stored flag state. Court_id is async (populateCourtPicker fetches
+  // courts from the API) so it restores via the .then() below + a
+  // follow-up recalc when the picker is ready.
+  restoreFlagsForProceeding();
 
   setProceedingPickerCollapsed(true, proceedingDisplayName(btn));
 
   showStep(2);
   scheduleCalc(0);
+
+  void populateCourtPicker("court-picker-row", "court-picker", selectedType).then(() => {
+    if (restoreCourtForProceeding()) scheduleCalc(0);
+  });
+}
+
+// restoreFlagsForProceeding seeds the proceeding-specific flag
+// checkboxes from localStorage. Mirrors syncFlagRows in scope — only
+// flags currently visible for the active proceeding are meaningful
+// (the hidden checkboxes still write to localStorage if toggled, but
+// that's impossible because they're not in the DOM as visible
+// controls). syncInfAmendEnabled enforces the upc.inf.cfi inf-amend
+// gating after the restore.
+function restoreFlagsForProceeding(): void {
+  const flagPairs: Array<[string, string]> = [
+    ["ccr-flag",       SCENARIO_KEYS.ccr],
+    ["inf-amend-flag", SCENARIO_KEYS.infAmend],
+    ["rev-amend-flag", SCENARIO_KEYS.revAmend],
+    ["rev-cci-flag",   SCENARIO_KEYS.revCci],
+  ];
+  for (const [domId, storageKey] of flagPairs) {
+    const cb = document.getElementById(domId) as HTMLInputElement | null;
+    if (!cb) continue;
+    cb.checked = readBoolFlag(scenarioStorage, storageKey);
+  }
+  syncInfAmendEnabled();
+}
+
+// restoreCourtForProceeding tries to apply the localStorage court_id
+// to the picker after populateCourtPicker resolves. Returns true iff
+// a value actually changed (so the caller can schedule a follow-up
+// calc). Skips silently when the picker is hidden, the stored ID isn't
+// in the options list (court rotated since last visit), or the picker
+// already happens to be on the stored value.
+function restoreCourtForProceeding(): boolean {
+  const courtPicker = document.getElementById("court-picker") as HTMLSelectElement | null;
+  const storedCourtId = readCourtId(scenarioStorage);
+  if (!courtPicker || !storedCourtId) return false;
+  const has = Array.from(courtPicker.options).some((o) => o.value === storedCourtId);
+  if (!has) return false;
+  if (courtPicker.value === storedCourtId) return false;
+  courtPicker.value = storedCourtId;
+  return true;
 }
 
 // Slice B1 (m/paliad#124 §18.1) — Berufung unification.
@@ -606,7 +633,7 @@ function syncAppealTargetRowVisibility() {
   row.style.display = visible ? "" : "none";
   if (!visible && currentAppealTarget !== "") {
     currentAppealTarget = "";
-    writeAppealTargetToURL("");
+    applyURLFilters({ target: "" });
     syncRadioGroup("appeal-target", "endentscheidung");
   }
 }
@@ -720,11 +747,11 @@ function showSideRadioCluster() {
 // already chosen and we never overwrite. When we do prefill, write the
 // derived side to the URL so reload + back/forward round-trip cleanly.
 function applySidePrefill(os: ProjectOurSide["our_side"] | undefined) {
-  if (readSideFromURL() !== null) return;
+  if (parseSideFromSearch(window.location.search) !== null) return;
   const next = ourSideToSide(os);
   if (next === null) return;
   currentSide = next;
-  writeSideToURL(next);
+  applyURLFilters({ side: next });
   syncRadioGroup("side", next);
   sidePrefilledFromProject = true;
   renderSideChip(next);
@@ -793,8 +820,8 @@ function initViewToggle() {
 // /api/tools/fristenrechner round-trip — perspective is a pure
 // projection of the last response, no backend involved.
 function initPerspectiveControls() {
-  currentSide = readSideFromURL();
-  currentAppealTarget = readAppealTargetFromURL();
+  currentSide = parseSideFromSearch(window.location.search);
+  currentAppealTarget = parseAppealTargetFromSearch(window.location.search);
   syncRadioGroup("side", currentSide ?? "");
   syncRadioGroup("appeal-target", currentAppealTarget || "endentscheidung");
   syncSideHintVisibility();
@@ -804,7 +831,7 @@ function initPerspectiveControls() {
       if (!input.checked) return;
       const v = input.value;
       currentSide = (v === "claimant" || v === "defendant") ? v : null;
-      writeSideToURL(currentSide);
+      applyURLFilters({ side: currentSide });
       syncSideHintVisibility();
       if (lastResponse) renderResults(lastResponse);
     });
@@ -822,7 +849,7 @@ function initPerspectiveControls() {
       } else {
         currentAppealTarget = "";
       }
-      writeAppealTargetToURL(currentAppealTarget);
+      applyURLFilters({ target: currentAppealTarget });
       scheduleCalc(0);
     });
   });
@@ -844,28 +871,57 @@ document.addEventListener("DOMContentLoaded", () => {
 
   const dateInput = document.getElementById("trigger-date") as HTMLInputElement | null;
   if (dateInput) {
-    dateInput.addEventListener("change", () => scheduleCalc());
-    dateInput.addEventListener("input", () => scheduleCalc());
+    // Hydrate trigger_date from URL on first paint so a refresh /
+    // shared link reproduces the same dated timeline. URL wins over
+    // the verfahrensablauf.tsx today-default that the <input> renders
+    // with. parseTriggerDateFromSearch validates the shape so a
+    // malformed link silently falls back to the today-default.
+    const urlDate = parseTriggerDateFromSearch(window.location.search);
+    if (urlDate) dateInput.value = urlDate;
+    const persistDate = () => {
+      applyURLFilters({ triggerDate: dateInput.value });
+    };
+    dateInput.addEventListener("change", () => { persistDate(); scheduleCalc(); });
+    dateInput.addEventListener("input", () => { persistDate(); scheduleCalc(); });
     dateInput.addEventListener("keydown", (e) => {
-      if ((e as KeyboardEvent).key === "Enter") scheduleCalc(0);
+      if ((e as KeyboardEvent).key === "Enter") { persistDate(); scheduleCalc(0); }
     });
   }
 
   const courtPicker = document.getElementById("court-picker") as HTMLSelectElement | null;
-  if (courtPicker) courtPicker.addEventListener("change", () => scheduleCalc(0));
+  if (courtPicker) courtPicker.addEventListener("change", () => {
+    writeCourtId(scenarioStorage, courtPicker.value);
+    scheduleCalc(0);
+  });
 
   // Flag-checkbox listeners — each flip triggers a fresh calc so the
   // timeline re-projects with the new gating. ccr-flag additionally
-  // enables/disables the nested inf-amend row.
+  // enables/disables the nested inf-amend row. Each flip also writes
+  // through to localStorage so the choice survives a reload (URL stays
+  // clean; flags are scenario state, not filter chips — t-paliad-308).
   const ccrFlag = document.getElementById("ccr-flag") as HTMLInputElement | null;
   if (ccrFlag) ccrFlag.addEventListener("change", () => {
+    writeBoolFlag(scenarioStorage, SCENARIO_KEYS.ccr, ccrFlag.checked);
     syncInfAmendEnabled();
+    // Disabling ccr also unchecks inf-amend (see syncInfAmendEnabled).
+    // Mirror that into storage so the next reload doesn't repopulate a
+    // disabled checkbox as checked.
+    const infAmend = document.getElementById("inf-amend-flag") as HTMLInputElement | null;
+    if (infAmend) writeBoolFlag(scenarioStorage, SCENARIO_KEYS.infAmend, infAmend.checked);
     scheduleCalc(0);
   });
-  (["inf-amend-flag", "rev-amend-flag", "rev-cci-flag"]).forEach((id) => {
+  const flagStorageKeys: Record<string, string> = {
+    "inf-amend-flag": SCENARIO_KEYS.infAmend,
+    "rev-amend-flag": SCENARIO_KEYS.revAmend,
+    "rev-cci-flag":   SCENARIO_KEYS.revCci,
+  };
+  for (const [id, storageKey] of Object.entries(flagStorageKeys)) {
     const cb = document.getElementById(id) as HTMLInputElement | null;
-    if (cb) cb.addEventListener("change", () => scheduleCalc(0));
-  });
+    if (cb) cb.addEventListener("change", () => {
+      writeBoolFlag(scenarioStorage, storageKey, cb.checked);
+      scheduleCalc(0);
+    });
+  }
 
   document.getElementById("fristen-print-btn")?.addEventListener("click", () => window.print());
 
@@ -909,16 +965,17 @@ document.addEventListener("DOMContentLoaded", () => {
     });
   }
 
-  // t-paliad-290 — show-hidden toggle. Hydrate from URL, wire change
-  // to URL + recalc (the backend reshapes the response — we can't just
-  // re-render lastResponse since the hidden rows aren't in it when the
-  // toggle was OFF).
+  // t-paliad-290 — show-hidden toggle. Hydrated from localStorage at
+  // module load (showHidden); each flip writes back to localStorage
+  // and triggers a recalc (the backend reshapes the response — we
+  // can't just re-render lastResponse since the hidden rows aren't
+  // in it when the toggle was OFF).
   const showHiddenCb = document.getElementById("show-hidden-toggle") as HTMLInputElement | null;
   if (showHiddenCb) {
     showHiddenCb.checked = showHidden;
     showHiddenCb.addEventListener("change", () => {
       showHidden = showHiddenCb.checked;
-      writeShowHiddenToURL(showHidden);
+      writeBoolFlag(scenarioStorage, SCENARIO_KEYS.showHidden, showHidden);
       scheduleCalc(0);
     });
   }
@@ -926,11 +983,10 @@ document.addEventListener("DOMContentLoaded", () => {
   initViewToggle();
   initPerspectiveControls();
 
-  // t-paliad-265 — per-event-card choices. Unbound surface, so commits
-  // mutate the in-memory list + URL, then trigger a recalc. The
-  // popover module owns the popover lifecycle; this page owns the
-  // recalc + URL plumbing.
-  perCardChoices = readChoicesFromURL();
+  // t-paliad-265 — per-event-card choices. Unbound surface; persistence
+  // is localStorage-only (t-paliad-308) so a shared link doesn't carry
+  // the recipient's per-card tweaks. The popover module owns the
+  // popover lifecycle; this page owns the recalc + storage plumbing.
   const timelineEl = document.getElementById("timeline-container");
   if (timelineEl) {
     attachEventCardChoices({
@@ -941,14 +997,14 @@ document.addEventListener("DOMContentLoaded", () => {
           (c) => !(c.submission_code === choice.submission_code && c.choice_kind === choice.choice_kind),
         );
         perCardChoices.push(choice);
-        writeChoicesToURL(perCardChoices);
+        writeEventChoices(scenarioStorage, perCardChoices);
         scheduleCalc(0);
       },
       remove: (submissionCode, kind) => {
         perCardChoices = perCardChoices.filter(
           (c) => !(c.submission_code === submissionCode && c.choice_kind === kind),
         );
-        writeChoicesToURL(perCardChoices);
+        writeEventChoices(scenarioStorage, perCardChoices);
         scheduleCalc(0);
       },
     });
@@ -984,8 +1040,31 @@ document.addEventListener("DOMContentLoaded", () => {
     syncTriggerEventLabel();
   });
 
-  // Pre-select the first proceeding tile so users see a timeline
-  // immediately on landing — matches /tools/fristenrechner behaviour.
-  const firstBtn = document.querySelector<HTMLButtonElement>(".proceeding-btn");
-  if (firstBtn) selectProceeding(firstBtn);
+  // Pre-select the proceeding tile. URL wins: if ?proceeding= is set
+  // and points at a known tile, that tile is selected without rewriting
+  // the URL. Otherwise fall back to the first tile so users see a
+  // timeline immediately on landing — matches /tools/fristenrechner
+  // behaviour. The auto-pick does NOT write the URL so the default
+  // landing stays clean (`?proceeding=` only appears once the user
+  // makes an explicit choice). (t-paliad-308 / m/paliad#137)
+  const urlProceeding = parseProceedingFromSearch(window.location.search);
+  let initialBtn: HTMLButtonElement | null = null;
+  let urlHit = false;
+  if (urlProceeding) {
+    initialBtn = document.querySelector<HTMLButtonElement>(
+      `.proceeding-btn[data-code="${urlProceeding.replace(/"/g, '\\"')}"]`,
+    );
+    urlHit = initialBtn !== null;
+  }
+  if (!initialBtn) {
+    initialBtn = document.querySelector<HTMLButtonElement>(".proceeding-btn");
+  }
+  if (initialBtn) {
+    // writeURL=false when the URL either already carries this code
+    // (no churn) or has no proceeding (auto-default → don't pollute
+    // the clean URL). Only an unknown / stale ?proceeding= triggers
+    // a rewrite so the URL converges on the resolved tile.
+    const writeURL = urlProceeding !== "" && !urlHit;
+    selectProceeding(initialBtn, { writeURL });
+  }
 });

frontend/src/client/views/verfahrensablauf-state.test.ts

@@ -0,0 +1,309 @@
+// Unit tests for the /tools/verfahrensablauf URL + scenario-localStorage
+// state contract (t-paliad-308 / m/paliad#137). Run with `bun test`.
+//
+// The contract:
+//   1. URL params (proceeding, side, target, trigger_date) define which
+//      timeline kind the user is looking at — paste-able, shareable,
+//      refresh-resistant.
+//   2. localStorage (paliad.verfahrensablauf.scenario.*) holds the
+//      per-user scenario tweaks (event_choices, court_id, flags,
+//      show_hidden) — these never leak into a shared link.
+//   3. On hydrate, URL wins. localStorage fills the rest.
+
+import { describe, expect, test } from "bun:test";
+import {
+  APPEAL_TARGETS,
+  SCENARIO_KEYS,
+  SCENARIO_PREFIX,
+  URL_KEYS,
+  applyFiltersToSearch,
+  hydrate,
+  makeMemoryStorage,
+  parseAppealTargetFromSearch,
+  parseProceedingFromSearch,
+  parseSideFromSearch,
+  parseTriggerDateFromSearch,
+  readBoolFlag,
+  readCourtId,
+  readEventChoices,
+  readScenario,
+  writeBoolFlag,
+  writeCourtId,
+  writeEventChoices,
+} from "./verfahrensablauf-state";
+
+describe("URL parsers — filter chips", () => {
+  test("parseProceedingFromSearch returns empty string when absent", () => {
+    expect(parseProceedingFromSearch("")).toBe("");
+    expect(parseProceedingFromSearch("?side=claimant")).toBe("");
+  });
+
+  test("parseProceedingFromSearch echoes the raw value", () => {
+    expect(parseProceedingFromSearch("?proceeding=upc.inf.cfi")).toBe("upc.inf.cfi");
+    expect(parseProceedingFromSearch("?proceeding=upc.apl.unified&side=claimant")).toBe("upc.apl.unified");
+  });
+
+  test("parseSideFromSearch validates the enum", () => {
+    expect(parseSideFromSearch("?side=claimant")).toBe("claimant");
+    expect(parseSideFromSearch("?side=defendant")).toBe("defendant");
+    expect(parseSideFromSearch("?side=neither")).toBe(null);
+    expect(parseSideFromSearch("")).toBe(null);
+  });
+
+  test("parseAppealTargetFromSearch only accepts canonical slugs", () => {
+    for (const t of APPEAL_TARGETS) {
+      expect(parseAppealTargetFromSearch(`?target=${t}`)).toBe(t);
+    }
+    expect(parseAppealTargetFromSearch("?target=unknown")).toBe("");
+    expect(parseAppealTargetFromSearch("")).toBe("");
+  });
+
+  test("parseTriggerDateFromSearch validates the ISO-date shape", () => {
+    expect(parseTriggerDateFromSearch("?trigger_date=2026-05-26")).toBe("2026-05-26");
+    expect(parseTriggerDateFromSearch("?trigger_date=2024-02-29")).toBe("2024-02-29"); // leap year
+  });
+
+  test("parseTriggerDateFromSearch rejects malformed and impossible dates", () => {
+    expect(parseTriggerDateFromSearch("?trigger_date=2026-02-30")).toBe(""); // Feb 30
+    expect(parseTriggerDateFromSearch("?trigger_date=2026-13-01")).toBe(""); // month 13
+    expect(parseTriggerDateFromSearch("?trigger_date=tomorrow")).toBe("");
+    expect(parseTriggerDateFromSearch("?trigger_date=2026-5-26")).toBe(""); // 1-digit month
+    expect(parseTriggerDateFromSearch("")).toBe("");
+  });
+});
+
+describe("URL encoder — applyFiltersToSearch", () => {
+  test("empty filters preserve the existing query string", () => {
+    expect(applyFiltersToSearch("?other=keep", {})).toBe("?other=keep");
+  });
+
+  test("setting a filter writes the canonical key", () => {
+    expect(applyFiltersToSearch("", { proceeding: "upc.inf.cfi" })).toBe("?proceeding=upc.inf.cfi");
+    expect(applyFiltersToSearch("", { side: "claimant" })).toBe("?side=claimant");
+    expect(applyFiltersToSearch("", { target: "endentscheidung" })).toBe("?target=endentscheidung");
+    expect(applyFiltersToSearch("", { triggerDate: "2026-05-26" })).toBe("?trigger_date=2026-05-26");
+  });
+
+  test("setting null / empty / undefined deletes the key", () => {
+    expect(applyFiltersToSearch("?side=claimant", { side: null })).toBe("");
+    expect(applyFiltersToSearch("?proceeding=upc.inf.cfi", { proceeding: "" })).toBe("");
+    expect(applyFiltersToSearch("?target=endentscheidung", { target: "" })).toBe("");
+    expect(applyFiltersToSearch("?trigger_date=2026-05-26", { triggerDate: "" })).toBe("");
+  });
+
+  test("invalid trigger_date is deleted (never written as-is)", () => {
+    expect(applyFiltersToSearch("?trigger_date=2026-05-26", { triggerDate: "bogus" })).toBe("");
+  });
+
+  test("setting all four filters together emits all four keys", () => {
+    const out = applyFiltersToSearch("", {
+      proceeding: "upc.apl.unified",
+      side: "defendant",
+      target: "endentscheidung",
+      triggerDate: "2026-05-26",
+    });
+    expect(out).toContain("proceeding=upc.apl.unified");
+    expect(out).toContain("side=defendant");
+    expect(out).toContain("target=endentscheidung");
+    expect(out).toContain("trigger_date=2026-05-26");
+  });
+
+  test("other params (project, view) are preserved", () => {
+    const out = applyFiltersToSearch("?project=abc&view=timeline", { side: "claimant" });
+    expect(out).toContain("project=abc");
+    expect(out).toContain("view=timeline");
+    expect(out).toContain("side=claimant");
+  });
+
+  test("absent keys in the filter object don't touch existing URL values", () => {
+    // Only updating side — proceeding should be untouched.
+    const out = applyFiltersToSearch("?proceeding=upc.inf.cfi&side=defendant", { side: "claimant" });
+    expect(out).toContain("proceeding=upc.inf.cfi");
+    expect(out).toContain("side=claimant");
+  });
+});
+
+describe("URL round-trip — encode then parse yields the same value", () => {
+  test("proceeding", () => {
+    const enc = applyFiltersToSearch("", { proceeding: "upc.inf.cfi" });
+    expect(parseProceedingFromSearch(enc)).toBe("upc.inf.cfi");
+  });
+
+  test("side", () => {
+    const enc = applyFiltersToSearch("", { side: "defendant" });
+    expect(parseSideFromSearch(enc)).toBe("defendant");
+  });
+
+  test("target", () => {
+    const enc = applyFiltersToSearch("", { target: "kostenentscheidung" });
+    expect(parseAppealTargetFromSearch(enc)).toBe("kostenentscheidung");
+  });
+
+  test("trigger_date", () => {
+    const enc = applyFiltersToSearch("", { triggerDate: "2026-05-26" });
+    expect(parseTriggerDateFromSearch(enc)).toBe("2026-05-26");
+  });
+});
+
+describe("Scenario localStorage helpers", () => {
+  test("SCENARIO_PREFIX is paliad.verfahrensablauf.scenario and all keys live under it", () => {
+    expect(SCENARIO_PREFIX).toBe("paliad.verfahrensablauf.scenario");
+    for (const key of Object.values(SCENARIO_KEYS)) {
+      expect(key.startsWith(SCENARIO_PREFIX + ".")).toBe(true);
+    }
+  });
+
+  test("readEventChoices returns [] on empty storage", () => {
+    const s = makeMemoryStorage();
+    expect(readEventChoices(s)).toEqual([]);
+  });
+
+  test("writeEventChoices + readEventChoices round-trip", () => {
+    const s = makeMemoryStorage();
+    const choices = [
+      { submission_code: "upc.inf.cfi.r12", choice_kind: "appellant" as const, choice_value: "claimant" },
+      { submission_code: "upc.inf.cfi.r30", choice_kind: "include_ccr" as const, choice_value: "1" },
+    ];
+    writeEventChoices(s, choices);
+    expect(readEventChoices(s)).toEqual(choices);
+  });
+
+  test("writeEventChoices([]) clears the key (removeItem semantic, not empty string)", () => {
+    const s = makeMemoryStorage();
+    writeEventChoices(s, [{ submission_code: "r1", choice_kind: "skip", choice_value: "1" }]);
+    expect(s.getItem(SCENARIO_KEYS.eventChoices)).not.toBe(null);
+    writeEventChoices(s, []);
+    expect(s.getItem(SCENARIO_KEYS.eventChoices)).toBe(null);
+  });
+
+  test("readEventChoices ignores unknown choice_kind values", () => {
+    const s = makeMemoryStorage();
+    s.setItem(SCENARIO_KEYS.eventChoices, "r1:appellant=claimant,r2:bogus=x,r3:skip=1");
+    expect(readEventChoices(s)).toEqual([
+      { submission_code: "r1", choice_kind: "appellant", choice_value: "claimant" },
+      { submission_code: "r3", choice_kind: "skip", choice_value: "1" },
+    ]);
+  });
+
+  test("readCourtId returns '' on empty storage, echoes stored value otherwise", () => {
+    const s = makeMemoryStorage();
+    expect(readCourtId(s)).toBe("");
+    writeCourtId(s, "UPC-LD-MUC");
+    expect(readCourtId(s)).toBe("UPC-LD-MUC");
+  });
+
+  test("writeCourtId('') removes the key", () => {
+    const s = makeMemoryStorage();
+    writeCourtId(s, "UPC-LD-MUC");
+    expect(s.getItem(SCENARIO_KEYS.courtId)).toBe("UPC-LD-MUC");
+    writeCourtId(s, "");
+    expect(s.getItem(SCENARIO_KEYS.courtId)).toBe(null);
+  });
+
+  test("readBoolFlag / writeBoolFlag round-trip with removeItem on false", () => {
+    const s = makeMemoryStorage();
+    expect(readBoolFlag(s, SCENARIO_KEYS.ccr)).toBe(false);
+    writeBoolFlag(s, SCENARIO_KEYS.ccr, true);
+    expect(readBoolFlag(s, SCENARIO_KEYS.ccr)).toBe(true);
+    expect(s.getItem(SCENARIO_KEYS.ccr)).toBe("1");
+    writeBoolFlag(s, SCENARIO_KEYS.ccr, false);
+    expect(readBoolFlag(s, SCENARIO_KEYS.ccr)).toBe(false);
+    expect(s.getItem(SCENARIO_KEYS.ccr)).toBe(null);
+  });
+
+  test("readScenario returns all fields defaulted on empty storage", () => {
+    const s = makeMemoryStorage();
+    expect(readScenario(s)).toEqual({
+      eventChoices: [],
+      courtId: "",
+      ccr: false,
+      infAmend: false,
+      revAmend: false,
+      revCci: false,
+      showHidden: false,
+    });
+  });
+});
+
+describe("Hydration order — URL wins, localStorage fills the rest", () => {
+  test("URL fills filter chips, localStorage fills scenario state", () => {
+    const s = makeMemoryStorage();
+    writeCourtId(s, "UPC-LD-MUC");
+    writeBoolFlag(s, SCENARIO_KEYS.showHidden, true);
+    writeBoolFlag(s, SCENARIO_KEYS.ccr, true);
+    const out = hydrate(
+      "?proceeding=upc.inf.cfi&side=defendant&target=endentscheidung&trigger_date=2026-05-26",
+      s,
+    );
+    // URL-sourced
+    expect(out.proceeding).toBe("upc.inf.cfi");
+    expect(out.side).toBe("defendant");
+    expect(out.target).toBe("endentscheidung");
+    expect(out.triggerDate).toBe("2026-05-26");
+    // localStorage-sourced
+    expect(out.courtId).toBe("UPC-LD-MUC");
+    expect(out.showHidden).toBe(true);
+    expect(out.ccr).toBe(true);
+  });
+
+  test("absent URL → all filter fields are empty/null, localStorage still hydrates scenario", () => {
+    const s = makeMemoryStorage();
+    writeCourtId(s, "UPC-LD-MUC");
+    const out = hydrate("", s);
+    expect(out.proceeding).toBe("");
+    expect(out.side).toBe(null);
+    expect(out.target).toBe("");
+    expect(out.triggerDate).toBe("");
+    expect(out.courtId).toBe("UPC-LD-MUC");
+  });
+
+  test("absent localStorage → URL still fills filter chips, scenario defaults", () => {
+    const s = makeMemoryStorage();
+    const out = hydrate(
+      "?proceeding=upc.apl.unified&side=claimant&target=anordnung&trigger_date=2026-07-01",
+      s,
+    );
+    expect(out.proceeding).toBe("upc.apl.unified");
+    expect(out.side).toBe("claimant");
+    expect(out.target).toBe("anordnung");
+    expect(out.triggerDate).toBe("2026-07-01");
+    expect(out.courtId).toBe("");
+    expect(out.eventChoices).toEqual([]);
+    expect(out.showHidden).toBe(false);
+  });
+
+  test("a shared link doesn't leak the recipient's scenario state in", () => {
+    // Two storages: m's (loaded with court + flags) and a recipient's
+    // (empty). The same URL should reproduce filter chips identically
+    // but leave each user's scenario state untouched.
+    const mStorage = makeMemoryStorage();
+    writeCourtId(mStorage, "UPC-LD-MUC");
+    writeBoolFlag(mStorage, SCENARIO_KEYS.ccr, true);
+    const recipientStorage = makeMemoryStorage();
+
+    const sharedURL = "?proceeding=upc.inf.cfi&side=defendant&trigger_date=2026-05-26";
+
+    const mView = hydrate(sharedURL, mStorage);
+    const recipientView = hydrate(sharedURL, recipientStorage);
+
+    // Filter chips identical
+    expect(mView.proceeding).toBe(recipientView.proceeding);
+    expect(mView.side).toBe(recipientView.side);
+    expect(mView.triggerDate).toBe(recipientView.triggerDate);
+
+    // Scenario state diverges — recipient sees defaults
+    expect(mView.courtId).toBe("UPC-LD-MUC");
+    expect(recipientView.courtId).toBe("");
+    expect(mView.ccr).toBe(true);
+    expect(recipientView.ccr).toBe(false);
+  });
+});
+
+describe("URL key constants match the documented contract", () => {
+  test("URL_KEYS uses the spec'd snake_case names", () => {
+    expect(URL_KEYS.proceeding).toBe("proceeding");
+    expect(URL_KEYS.side).toBe("side");
+    expect(URL_KEYS.target).toBe("target");
+    expect(URL_KEYS.triggerDate).toBe("trigger_date");
+  });
+});

frontend/src/client/views/verfahrensablauf-state.ts

@@ -0,0 +1,263 @@
+// /tools/verfahrensablauf URL + scenario-localStorage state contract
+// (t-paliad-308 / m/paliad#137). Splits the page's persisted state into
+// two namespaces:
+//
+//   URL params (filter chips — the timeline kind the user is looking
+//   at; paste-able, shareable, refresh-resistant):
+//     proceeding, side, target, trigger_date
+//
+//   localStorage `paliad.verfahrensablauf.scenario.*` (per-user
+//   scenario inputs — the noisy parts that don't belong in a URL):
+//     event_choices, court_id, ccr, inf_amend, rev_amend, rev_cci,
+//     show_hidden
+//
+// Hydration order: URL wins. On page load, URL fills the filter chips;
+// localStorage fills the rest. Filter-chip changes write to URL only.
+// Scenario changes write to localStorage only. A shared link from a
+// colleague reproduces the timeline kind (proceeding + side + target +
+// trigger_date) but never leaks the recipient's court / flag /
+// event_choices state in.
+//
+// All helpers in this module are pure: they take a search string (or a
+// StorageLike) and return values, no DOM. The wiring in
+// ../verfahrensablauf.ts mounts them onto window.location +
+// window.localStorage at runtime.
+
+import type { EventChoice, ChoiceKind } from "./event-card-choices";
+
+// ----- URL params (filter chips) ----------------------------------
+
+export type Side = "claimant" | "defendant" | null;
+
+export const APPEAL_TARGETS = [
+  "endentscheidung",
+  "kostenentscheidung",
+  "anordnung",
+  "schadensbemessung",
+  "bucheinsicht",
+] as const;
+export type AppealTarget = (typeof APPEAL_TARGETS)[number] | "";
+
+export const URL_KEYS = {
+  proceeding: "proceeding",
+  side: "side",
+  target: "target",
+  triggerDate: "trigger_date",
+} as const;
+
+// parseProceedingFromSearch extracts the proceeding code. Returns ""
+// if absent. No validation against the proceeding registry — that's
+// the caller's job (an unknown code from a stale link should leave
+// the first-tile auto-select fallback running).
+export function parseProceedingFromSearch(search: string): string {
+  const v = new URLSearchParams(search).get(URL_KEYS.proceeding);
+  return v ?? "";
+}
+
+export function parseSideFromSearch(search: string): Side {
+  const raw = new URLSearchParams(search).get(URL_KEYS.side);
+  return raw === "claimant" || raw === "defendant" ? raw : null;
+}
+
+export function parseAppealTargetFromSearch(search: string): AppealTarget {
+  const raw = new URLSearchParams(search).get(URL_KEYS.target) || "";
+  if ((APPEAL_TARGETS as readonly string[]).includes(raw)) {
+    return raw as AppealTarget;
+  }
+  return "";
+}
+
+// parseTriggerDateFromSearch validates the ISO-date shape so a
+// malformed link can't poison the date input. Accepts "YYYY-MM-DD"
+// only. Round-tripped against Date to reject 2026-02-30 etc.
+export function parseTriggerDateFromSearch(search: string): string {
+  const raw = new URLSearchParams(search).get(URL_KEYS.triggerDate) || "";
+  if (!/^\d{4}-\d{2}-\d{2}$/.test(raw)) return "";
+  const d = new Date(raw + "T00:00:00Z");
+  if (Number.isNaN(d.getTime())) return "";
+  if (d.toISOString().slice(0, 10) !== raw) return "";
+  return raw;
+}
+
+// applyFiltersToSearch produces the canonical query string for the
+// four URL-owned params. Other params (e.g. ?view=, ?project=) are
+// preserved verbatim. Empty values are deleted, never written as
+// empty string, so the URL stays clean on the default.
+export function applyFiltersToSearch(
+  search: string,
+  filters: { proceeding?: string; side?: Side; target?: AppealTarget; triggerDate?: string },
+): string {
+  const params = new URLSearchParams(search);
+  if ("proceeding" in filters) {
+    if (filters.proceeding && filters.proceeding !== "") {
+      params.set(URL_KEYS.proceeding, filters.proceeding);
+    } else {
+      params.delete(URL_KEYS.proceeding);
+    }
+  }
+  if ("side" in filters) {
+    if (filters.side === "claimant" || filters.side === "defendant") {
+      params.set(URL_KEYS.side, filters.side);
+    } else {
+      params.delete(URL_KEYS.side);
+    }
+  }
+  if ("target" in filters) {
+    if (filters.target && filters.target !== "") {
+      params.set(URL_KEYS.target, filters.target);
+    } else {
+      params.delete(URL_KEYS.target);
+    }
+  }
+  if ("triggerDate" in filters) {
+    if (filters.triggerDate && /^\d{4}-\d{2}-\d{2}$/.test(filters.triggerDate)) {
+      params.set(URL_KEYS.triggerDate, filters.triggerDate);
+    } else {
+      params.delete(URL_KEYS.triggerDate);
+    }
+  }
+  const s = params.toString();
+  return s ? `?${s}` : "";
+}
+
+// ----- localStorage (scenario state) ------------------------------
+
+export const SCENARIO_PREFIX = "paliad.verfahrensablauf.scenario";
+export const SCENARIO_KEYS = {
+  eventChoices: `${SCENARIO_PREFIX}.event_choices`,
+  courtId: `${SCENARIO_PREFIX}.court_id`,
+  ccr: `${SCENARIO_PREFIX}.ccr`,
+  infAmend: `${SCENARIO_PREFIX}.inf_amend`,
+  revAmend: `${SCENARIO_PREFIX}.rev_amend`,
+  revCci: `${SCENARIO_PREFIX}.rev_cci`,
+  showHidden: `${SCENARIO_PREFIX}.show_hidden`,
+} as const;
+
+// StorageLike is the tiny subset of the Web Storage API the scenario
+// helpers actually use. Lets the tests pass a Map-backed fake without
+// pulling in a full localStorage polyfill.
+export interface StorageLike {
+  getItem(key: string): string | null;
+  setItem(key: string, value: string): void;
+  removeItem(key: string): void;
+}
+
+// readEventChoices is forgiving: malformed tuples or unknown
+// choice_kinds are dropped silently. Same shape as the legacy URL
+// codec (comma-separated `submission_code:kind=value`).
+export function readEventChoices(storage: StorageLike): EventChoice[] {
+  const raw = storage.getItem(SCENARIO_KEYS.eventChoices);
+  if (!raw) return [];
+  const out: EventChoice[] = [];
+  for (const tuple of raw.split(",")) {
+    const m = tuple.match(/^([^:]+):([^=]+)=(.+)$/);
+    if (!m) continue;
+    const kind = m[2] as ChoiceKind;
+    if (kind !== "appellant" && kind !== "include_ccr" && kind !== "skip") continue;
+    out.push({ submission_code: m[1], choice_kind: kind, choice_value: m[3] });
+  }
+  return out;
+}
+
+export function writeEventChoices(storage: StorageLike, choices: EventChoice[]): void {
+  if (choices.length === 0) {
+    storage.removeItem(SCENARIO_KEYS.eventChoices);
+    return;
+  }
+  const enc = choices
+    .map((c) => `${c.submission_code}:${c.choice_kind}=${c.choice_value}`)
+    .join(",");
+  storage.setItem(SCENARIO_KEYS.eventChoices, enc);
+}
+
+// readCourtId / writeCourtId — empty string == no court picked. The
+// "" value is stored as a removed key, not an empty string entry, so
+// reading it back yields null rather than "".
+export function readCourtId(storage: StorageLike): string {
+  return storage.getItem(SCENARIO_KEYS.courtId) ?? "";
+}
+
+export function writeCourtId(storage: StorageLike, courtId: string): void {
+  if (courtId === "") {
+    storage.removeItem(SCENARIO_KEYS.courtId);
+    return;
+  }
+  storage.setItem(SCENARIO_KEYS.courtId, courtId);
+}
+
+// Boolean flags — "1" / "0" string encoding, removeItem on default
+// (false for flags, also false for show_hidden) so the storage stays
+// uncluttered on a fresh page.
+export function readBoolFlag(storage: StorageLike, key: string): boolean {
+  return storage.getItem(key) === "1";
+}
+
+export function writeBoolFlag(storage: StorageLike, key: string, on: boolean): void {
+  if (on) storage.setItem(key, "1");
+  else storage.removeItem(key);
+}
+
+// Read all scenario state in one call — convenience for the page's
+// load-time hydration. Caller decides whether to apply each field
+// (e.g. court_id is proceeding-specific; the page may discard the
+// stored value if the active proceeding doesn't expose a court row).
+export interface ScenarioState {
+  eventChoices: EventChoice[];
+  courtId: string;
+  ccr: boolean;
+  infAmend: boolean;
+  revAmend: boolean;
+  revCci: boolean;
+  showHidden: boolean;
+}
+
+export function readScenario(storage: StorageLike): ScenarioState {
+  return {
+    eventChoices: readEventChoices(storage),
+    courtId: readCourtId(storage),
+    ccr: readBoolFlag(storage, SCENARIO_KEYS.ccr),
+    infAmend: readBoolFlag(storage, SCENARIO_KEYS.infAmend),
+    revAmend: readBoolFlag(storage, SCENARIO_KEYS.revAmend),
+    revCci: readBoolFlag(storage, SCENARIO_KEYS.revCci),
+    showHidden: readBoolFlag(storage, SCENARIO_KEYS.showHidden),
+  };
+}
+
+// ----- URL → localStorage hydration order -------------------------
+
+// The page's load-time contract: read URL filters, then read
+// scenario state from localStorage. URL wins on conflict — but the
+// only field that can conflict is none of them today (URL owns
+// proceeding/side/target/trigger_date; localStorage owns the rest).
+// The order matters for one edge case: if a future field migrates
+// from URL → localStorage with overlap, the URL value MUST be honored.
+
+export interface HydratedState extends ScenarioState {
+  proceeding: string;
+  side: Side;
+  target: AppealTarget;
+  triggerDate: string;
+}
+
+export function hydrate(search: string, storage: StorageLike): HydratedState {
+  const scenario = readScenario(storage);
+  return {
+    proceeding: parseProceedingFromSearch(search),
+    side: parseSideFromSearch(search),
+    target: parseAppealTargetFromSearch(search),
+    triggerDate: parseTriggerDateFromSearch(search),
+    ...scenario,
+  };
+}
+
+// makeMemoryStorage — tiny StorageLike for tests / SSR fallback.
+// Not used by the runtime page (which mounts real localStorage), but
+// kept here so test files have one well-known import.
+export function makeMemoryStorage(): StorageLike {
+  const store = new Map<string, string>();
+  return {
+    getItem: (k) => (store.has(k) ? store.get(k)! : null),
+    setItem: (k, v) => { store.set(k, v); },
+    removeItem: (k) => { store.delete(k); },
+  };
+}

internal/db/migrations/139_deadline_rules_unified_view.down.sql

@@ -1,7 +0,0 @@
--- 139_deadline_rules_unified_view (down) — Slice B.3, t-paliad-305
---
--- Drops the view. The underlying paliad.sequencing_rules /
--- procedural_events / legal_sources tables are untouched (they own the
--- data — the view is just a projection).
-
-DROP VIEW IF EXISTS paliad.deadline_rules_unified;

internal/db/migrations/139_deadline_rules_unified_view.up.sql

@@ -1,122 +0,0 @@
--- 139_deadline_rules_unified_view — Slice B.3 read cutover (t-paliad-305 / m/paliad#93)
---
--- Creates paliad.deadline_rules_unified — a Postgres VIEW that
--- re-projects paliad.sequencing_rules + paliad.procedural_events +
--- paliad.legal_sources back into the legacy paliad.deadline_rules
--- column shape.
---
--- Why a view instead of rewriting every SELECT in Go:
---
---   - 19 read sites across 11 service files reference
---     paliad.deadline_rules. Rewriting each by hand multiplies the
---     opportunity for off-by-one bugs in the JOIN.
---   - The view has the same column names + types as the legacy table,
---     so the change in Go is a 1-token substitution per query
---     (FROM paliad.deadline_rules → FROM paliad.deadline_rules_unified)
---     with no struct or scanner changes.
---   - When B.4 drops paliad.deadline_rules, this view stays — it
---     becomes the canonical legacy-shape reader for any code that
---     hasn't been migrated to direct sr/pe/ls reads.
---
--- Column mapping (per design §4.2):
---   - id, proceeding_type_id, parent_id, primary_party, duration_*,
---     timing, sequence_order, is_spawn/court_set/bilateral, priority,
---     rule_code, rule_codes, deadline_notes(_en), condition_expr,
---     choices_offered, applies_to_target, trigger_event_id,
---     spawn_proceeding_type_id, anchor_alt, alt_duration_*,
---     alt_rule_code, combine_op, lifecycle_state, draft_of,
---     published_at, is_active, created_at, updated_at, spawn_label
---       → from paliad.sequencing_rules
---   - submission_code           → procedural_events.code
---   - name, name_en, description→ procedural_events
---   - event_type                → procedural_events.event_kind (renamed)
---   - concept_id                → procedural_events
---   - legal_source              → legal_sources.citation (via legal_source_id FK)
---
--- The view is READ-ONLY by default. Writes still go to the underlying
--- tables — RuleEditorService is refactored in the same slice to write
--- directly to sr/pe/ls. paliad.deadline_rules is FROZEN from B.3 onward
--- (no new writes); the dual-write helper from B.2 is decommissioned.
-
--- The CHECK constraint on sequencing_rules.primary_party doesn't exist
--- yet (mig 135 only constrained deadline_rules.primary_party). The view
--- inherits whatever value sr.primary_party carries; mig 136's backfill
--- set sr.primary_party = dr.primary_party so the canonical four-value
--- vocab is already in place. A later slice can add the same CHECK to
--- sequencing_rules itself.
-
-CREATE OR REPLACE VIEW paliad.deadline_rules_unified AS
-SELECT
-    sr.id,
-    sr.proceeding_type_id,
-    sr.parent_id,
-    pe.code                    AS submission_code,
-    pe.name,
-    pe.name_en,
-    pe.description,
-    sr.primary_party,
-    pe.event_kind              AS event_type,
-    sr.duration_value,
-    sr.duration_unit,
-    sr.timing,
-    sr.alt_duration_value,
-    sr.alt_duration_unit,
-    sr.alt_rule_code,
-    sr.anchor_alt,
-    sr.combine_op,
-    sr.rule_code,
-    sr.deadline_notes,
-    sr.deadline_notes_en,
-    sr.sequence_order,
-    sr.is_spawn,
-    sr.spawn_label,
-    sr.spawn_proceeding_type_id,
-    sr.is_bilateral,
-    sr.is_court_set,
-    sr.priority,
-    sr.condition_expr,
-    pe.concept_id,
-    ls.citation                AS legal_source,
-    sr.trigger_event_id,
-    sr.rule_codes,
-    sr.choices_offered,
-    sr.applies_to_target,
-    sr.lifecycle_state,
-    sr.draft_of,
-    sr.published_at,
-    sr.is_active,
-    sr.created_at,
-    sr.updated_at
-  FROM paliad.sequencing_rules sr
-  JOIN paliad.procedural_events pe ON pe.id = sr.procedural_event_id
-  LEFT JOIN paliad.legal_sources  ls ON ls.id = pe.legal_source_id;
-
-COMMENT ON VIEW paliad.deadline_rules_unified IS
-    'Slice B.3 (mig 139, t-paliad-305): legacy-shape projection over '
-    'sequencing_rules + procedural_events + legal_sources. Read-only — '
-    'writes go directly to the three underlying tables via '
-    'RuleEditorService. Survives B.4 destructive drop of '
-    'paliad.deadline_rules; the view will then be the only '
-    'legacy-shape reader.';
-
--- Post-apply integrity check: confirm the view's row count matches the
--- live sequencing_rules row count. A mismatch would indicate either a
--- mid-deploy race (rare) or a JOIN issue (the LEFT JOIN to legal_sources
--- never drops rows, the INNER JOIN to procedural_events drops sr rows
--- whose procedural_event_id is NULL — but that column is NOT NULL on
--- the table so it can't happen). Belt-and-braces.
-DO $$
-DECLARE
-    v_view_count int;
-    v_sr_count   int;
-BEGIN
-    SELECT COUNT(*) INTO v_view_count FROM paliad.deadline_rules_unified;
-    SELECT COUNT(*) INTO v_sr_count   FROM paliad.sequencing_rules;
-    IF v_view_count <> v_sr_count THEN
-        RAISE EXCEPTION '[mig 139] FAILED POST: view row count % does not match sequencing_rules row count %. '
-            'Possible cause: a sequencing_rules row references a procedural_event_id that does not exist (NOT NULL FK should prevent this).',
-            v_view_count, v_sr_count;
-    END IF;
-    RAISE NOTICE '[mig 139] view OK — deadline_rules_unified rows = % (= sequencing_rules)',
-        v_view_count;
-END $$;

internal/db/migrations/140_drop_deadline_rules.down.sql

@@ -1,47 +0,0 @@
--- 140_drop_deadline_rules (down) — Slice B.4, t-paliad-305
---
--- Best-effort recovery from the deadline_rules_pre_140 snapshot. The
--- original triggers (mig 079 audit), indexes, CHECK constraints (mig
--- 135 primary_party), and FK constraints on the new tables are NOT
--- recreated here — restoring the working state requires replaying
--- migrations 078/079/091/095/098/122/128/134/135 against the restored
--- table.
---
--- Use this only for catastrophic recovery. The normal revert path
--- for B.4 is to re-deploy the previous container image (which still
--- writes via the dual-write helper to a paliad.deadline_rules that no
--- longer exists) — that would crash on first write, so true revert
--- requires this down + a code revert + a snapshot restore.
-
--- Drop the INSTEAD OF triggers + functions
-DROP TRIGGER IF EXISTS deadline_rules_unified_insert ON paliad.deadline_rules_unified;
-DROP TRIGGER IF EXISTS deadline_rules_unified_update ON paliad.deadline_rules_unified;
-DROP FUNCTION IF EXISTS paliad.deadline_rules_unified_insert_trigger();
-DROP FUNCTION IF EXISTS paliad.deadline_rules_unified_update_trigger();
-
--- Recreate paliad.deadline_rules from snapshot.
-CREATE TABLE paliad.deadline_rules AS TABLE paliad.deadline_rules_pre_140;
-
--- Re-add the PK constraint (CREATE TABLE AS doesn't carry constraints).
-ALTER TABLE paliad.deadline_rules ADD PRIMARY KEY (id);
-
--- Re-point the FKs back to deadline_rules.
-ALTER TABLE paliad.appointments
-    DROP CONSTRAINT IF EXISTS appointments_deadline_rule_id_fkey;
-ALTER TABLE paliad.appointments
-    ADD CONSTRAINT appointments_deadline_rule_id_fkey
-        FOREIGN KEY (deadline_rule_id) REFERENCES paliad.deadline_rules(id);
-
-ALTER TABLE paliad.deadline_rule_backfill_orphans
-    DROP CONSTRAINT IF EXISTS deadline_rule_backfill_orphans_resolved_rule_id_fkey;
-ALTER TABLE paliad.deadline_rule_backfill_orphans
-    ADD CONSTRAINT deadline_rule_backfill_orphans_resolved_rule_id_fkey
-        FOREIGN KEY (resolved_rule_id) REFERENCES paliad.deadline_rules(id);
-
--- Re-add deadlines.rule_id from the snapshot's data (via sequencing_rule_id
--- which inherited deadline_rules.id during mig 136).
-ALTER TABLE paliad.deadlines ADD COLUMN rule_id uuid;
-UPDATE paliad.deadlines SET rule_id = sequencing_rule_id WHERE sequencing_rule_id IS NOT NULL;
-ALTER TABLE paliad.deadlines
-    ADD CONSTRAINT fristen_rule_id_fkey
-        FOREIGN KEY (rule_id) REFERENCES paliad.deadline_rules(id);

internal/db/migrations/140_drop_deadline_rules.up.sql

@@ -1,334 +0,0 @@
--- 140_drop_deadline_rules — Slice B.4 destructive drop (t-paliad-305 / m/paliad#93)
---
--- HARD STOPS:
---   * Audit-first: snapshot paliad.deadline_rules → paliad.deadline_rules_pre_140
---     in the SAME TRANSACTION as the DROP, per m's snapshot policy
---     (precedent migs 091/093/095/098). The whole .up.sql runs inside a
---     single transaction because the migration runner wraps it; if any
---     statement fails, the snapshot CREATE TABLE rolls back with the
---     destructive DROP.
---   * No data loss: paliad.deadline_rules has been a write-side shadow
---     since B.3 (B.2 dual-write keeps sequencing_rules + procedural_events
---     + legal_sources current). Drift verified clean before this slice
---     (deadline_rules=231, sequencing_rules=231, 0 mismatches across
---     counts/FKs/lifecycle/is_active).
---
--- What this migration does:
---   1. Snapshot deadline_rules → deadline_rules_pre_140 (preserves audit
---      trail of the table's final state for forensic + revert paths).
---   2. Final reconciliation: catch any deadlines whose
---      sequencing_rule_id/procedural_event_id columns drifted from the
---      legacy rule_id (no live drift today — defensive).
---   3. Drop the audit trigger on deadline_rules (it can't fire on a
---      gone table; the trigger function itself stays for the historical
---      paliad.deadline_rule_audit reads).
---   4. Re-point FKs that currently target deadline_rules.id over to
---      sequencing_rules.id. The id values are identical (sequencing_rules
---      inherited deadline_rules.id during mig 136 backfill), so no data
---      migration is needed — just the constraint swap. Affects:
---      - paliad.appointments.deadline_rule_id
---      - paliad.deadline_rule_backfill_orphans.resolved_rule_id
---   5. Drop paliad.deadlines.rule_id column. Per design §5.4 step 16:
---      "DROP COLUMN paliad.deadlines.rule_id (keep rule_code +
---      custom_rule_text as the human-readable denormalized columns —
---      they're the safety net for orphaned deadlines per t-paliad-258)."
---      The new sequencing_rule_id + procedural_event_id columns from
---      mig 136 are the FK back-links from B.4 forward.
---   6. DROP TABLE paliad.deadline_rules.
---   7. INSTEAD OF triggers on paliad.deadline_rules_unified that route
---      INSERTs/UPDATEs to the underlying sr+pe+ls tables. Lets the
---      RuleEditorService keep its existing SQL shape (one INSERT, one
---      UPDATE per write method) with only a table-name swap. The
---      triggers project the legacy column shape back to the three new
---      tables exactly as the dual-write helper did in B.2.
---
--- Down: best-effort restore from the snapshot. The original triggers,
--- indexes, and FKs are NOT recreated — operator must replay historical
--- migrations 078/079/091/095/098/122 to bring the table back to a
--- working shape. The down path is for catastrophic recovery, not casual
--- revert.
-
--- ---------------------------------------------------------------
--- 1. Snapshot — must precede the destructive ops (same TX).
--- ---------------------------------------------------------------
-
-CREATE TABLE paliad.deadline_rules_pre_140 AS TABLE paliad.deadline_rules;
-
-COMMENT ON TABLE paliad.deadline_rules_pre_140 IS
-    'Snapshot of paliad.deadline_rules taken in mig 140 (Slice B.4, '
-    't-paliad-305) before the destructive DROP. Mirrors precedent '
-    'pre_091/093/095/098. Read-only forensic + revert source.';
-
--- ---------------------------------------------------------------
--- 2. Final reconciliation — should be a no-op (drift was 0 going
---    into this slice). Belt-and-braces against a write that snuck
---    in between drift-check and this migration.
--- ---------------------------------------------------------------
-
-UPDATE paliad.deadlines d
-   SET sequencing_rule_id  = d.rule_id,
-       procedural_event_id = sr.procedural_event_id
-  FROM paliad.sequencing_rules sr
- WHERE sr.id = d.rule_id
-   AND d.rule_id IS NOT NULL
-   AND (d.sequencing_rule_id IS DISTINCT FROM d.rule_id
-        OR d.procedural_event_id IS DISTINCT FROM sr.procedural_event_id);
-
--- ---------------------------------------------------------------
--- 3. Drop the deadline_rules audit trigger. The trigger function
---    (paliad.deadline_rule_audit_trigger) stays defined for any
---    historical references; mig 079 created it.
--- ---------------------------------------------------------------
-
-DROP TRIGGER IF EXISTS deadline_rules_audit_aiud ON paliad.deadline_rules;
-
--- ---------------------------------------------------------------
--- 4. Re-point FKs from deadline_rules → sequencing_rules.
--- ---------------------------------------------------------------
-
-ALTER TABLE paliad.appointments
-    DROP CONSTRAINT IF EXISTS appointments_deadline_rule_id_fkey;
-ALTER TABLE paliad.appointments
-    ADD CONSTRAINT appointments_deadline_rule_id_fkey
-        FOREIGN KEY (deadline_rule_id) REFERENCES paliad.sequencing_rules(id);
-
-ALTER TABLE paliad.deadline_rule_backfill_orphans
-    DROP CONSTRAINT IF EXISTS deadline_rule_backfill_orphans_resolved_rule_id_fkey;
-ALTER TABLE paliad.deadline_rule_backfill_orphans
-    ADD CONSTRAINT deadline_rule_backfill_orphans_resolved_rule_id_fkey
-        FOREIGN KEY (resolved_rule_id) REFERENCES paliad.sequencing_rules(id);
-
--- Drop the deadlines→deadline_rules FK before we drop the column.
-ALTER TABLE paliad.deadlines
-    DROP CONSTRAINT IF EXISTS fristen_rule_id_fkey;
-
--- ---------------------------------------------------------------
--- 5. Drop paliad.deadlines.rule_id (column + remaining indexes).
--- ---------------------------------------------------------------
-
-ALTER TABLE paliad.deadlines
-    DROP COLUMN IF EXISTS rule_id;
-
--- ---------------------------------------------------------------
--- 6. DROP TABLE paliad.deadline_rules. Now that:
---    - dependent FKs are re-pointed to sequencing_rules,
---    - the audit trigger is dropped,
---    - deadlines.rule_id is gone,
---    nothing references the table anymore. The self-FKs
---    (deadline_rules.parent_id, .draft_of) drop with the table.
--- ---------------------------------------------------------------
-
-DROP TABLE paliad.deadline_rules;
-
--- ---------------------------------------------------------------
--- 7. INSTEAD OF triggers on the view — routes writes to sr+pe+ls.
--- ---------------------------------------------------------------
-
-CREATE OR REPLACE FUNCTION paliad.deadline_rules_unified_insert_trigger()
-RETURNS TRIGGER LANGUAGE plpgsql AS $fn$
-DECLARE
-    v_legal_source_id uuid;
-    v_pe_id           uuid;
-    v_code            text;
-BEGIN
-    -- legal_sources upsert (no-op if NEW.legal_source is NULL)
-    IF NEW.legal_source IS NOT NULL THEN
-        INSERT INTO paliad.legal_sources (citation, jurisdiction)
-        VALUES (NEW.legal_source,
-                COALESCE(NULLIF(split_part(NEW.legal_source, '.', 1), ''), 'other'))
-        ON CONFLICT (citation) DO NOTHING;
-        SELECT id INTO v_legal_source_id
-          FROM paliad.legal_sources
-         WHERE citation = NEW.legal_source;
-    END IF;
-
-    -- Mint synthetic code when submission_code is NULL — same recipe
-    -- as mig 136 + B.2 dual-write helper. Stays byte-identical.
-    v_code := COALESCE(NEW.submission_code,
-                       'null.' || substring(replace(NEW.id::text, '-', ''), 1, 8));
-
-    -- procedural_events upsert. ON CONFLICT (code) deliberately leaves
-    -- lifecycle_state / published_at / is_active alone — those track
-    -- the procedural-event concept's own lifecycle, not the inserting
-    -- sequencing-rule's lifecycle (e.g. a CloneAsDraft of a published
-    -- rule creates a draft sr that shares the published PE; the PE
-    -- should stay 'published'). Identity columns DO update so an
-    -- admin editing a draft's name still flips the lawyer-visible
-    -- label (1:1 today; revisit when 1:N becomes a real pattern).
-    INSERT INTO paliad.procedural_events
-        (code, name, name_en, description, event_kind, primary_party_default,
-         legal_source_id, concept_id, lifecycle_state, published_at, is_active)
-    VALUES
-        (v_code, NEW.name, NEW.name_en, NEW.description, NEW.event_type,
-         NEW.primary_party, v_legal_source_id, NEW.concept_id,
-         COALESCE(NEW.lifecycle_state, 'draft'), NEW.published_at,
-         COALESCE(NEW.is_active, true))
-    ON CONFLICT (code) DO UPDATE SET
-        name                  = EXCLUDED.name,
-        name_en               = EXCLUDED.name_en,
-        description           = EXCLUDED.description,
-        event_kind            = EXCLUDED.event_kind,
-        primary_party_default = EXCLUDED.primary_party_default,
-        legal_source_id       = EXCLUDED.legal_source_id,
-        concept_id            = EXCLUDED.concept_id,
-        -- lifecycle_state / published_at / is_active deliberately omitted
-        updated_at            = now()
-    RETURNING id INTO v_pe_id;
-
-    -- sequencing_rules insert. id is the caller-supplied NEW.id so
-    -- existing FK back-links (deadlines.sequencing_rule_id) resolve.
-    INSERT INTO paliad.sequencing_rules
-        (id, procedural_event_id, proceeding_type_id, parent_id, trigger_event_id,
-         duration_value, duration_unit, timing,
-         alt_duration_value, alt_duration_unit, alt_rule_code, anchor_alt,
-         combine_op, condition_expr, primary_party, sequence_order,
-         is_spawn, spawn_label, spawn_proceeding_type_id,
-         is_bilateral, is_court_set, priority,
-         rule_code, rule_codes, deadline_notes, deadline_notes_en,
-         choices_offered, applies_to_target,
-         lifecycle_state, draft_of, published_at, is_active,
-         created_at, updated_at)
-    VALUES
-        (NEW.id, v_pe_id, NEW.proceeding_type_id, NEW.parent_id, NEW.trigger_event_id,
-         COALESCE(NEW.duration_value, 0), COALESCE(NEW.duration_unit, 'months'),
-         COALESCE(NEW.timing, 'after'),
-         NEW.alt_duration_value, NEW.alt_duration_unit, NEW.alt_rule_code, NEW.anchor_alt,
-         NEW.combine_op, NEW.condition_expr, NEW.primary_party,
-         COALESCE(NEW.sequence_order, 0),
-         COALESCE(NEW.is_spawn, false), NEW.spawn_label, NEW.spawn_proceeding_type_id,
-         COALESCE(NEW.is_bilateral, false), COALESCE(NEW.is_court_set, false),
-         COALESCE(NEW.priority, 'mandatory'),
-         NEW.rule_code, NEW.rule_codes, NEW.deadline_notes, NEW.deadline_notes_en,
-         NEW.choices_offered, NEW.applies_to_target,
-         COALESCE(NEW.lifecycle_state, 'draft'), NEW.draft_of,
-         NEW.published_at, COALESCE(NEW.is_active, true),
-         COALESCE(NEW.created_at, now()), COALESCE(NEW.updated_at, now()));
-
-    RETURN NEW;
-END $fn$;
-
-CREATE TRIGGER deadline_rules_unified_insert
-    INSTEAD OF INSERT ON paliad.deadline_rules_unified
-    FOR EACH ROW EXECUTE FUNCTION paliad.deadline_rules_unified_insert_trigger();
-
-
-CREATE OR REPLACE FUNCTION paliad.deadline_rules_unified_update_trigger()
-RETURNS TRIGGER LANGUAGE plpgsql AS $fn$
-DECLARE
-    v_legal_source_id uuid;
-    v_code            text;
-BEGIN
-    -- legal_sources upsert (only if NEW.legal_source is non-NULL).
-    -- A change FROM non-NULL TO NULL clears legal_source_id on the
-    -- procedural_event below — same shape as mig 136 / B.2 behaviour.
-    IF NEW.legal_source IS NOT NULL THEN
-        INSERT INTO paliad.legal_sources (citation, jurisdiction)
-        VALUES (NEW.legal_source,
-                COALESCE(NULLIF(split_part(NEW.legal_source, '.', 1), ''), 'other'))
-        ON CONFLICT (citation) DO NOTHING;
-        SELECT id INTO v_legal_source_id
-          FROM paliad.legal_sources
-         WHERE citation = NEW.legal_source;
-    END IF;
-
-    v_code := COALESCE(NEW.submission_code,
-                       'null.' || substring(replace(NEW.id::text, '-', ''), 1, 8));
-
-    -- Update procedural_events keyed by the existing PE link on
-    -- sequencing_rules. lifecycle_state / published_at / is_active on
-    -- PE are NOT mirrored from the per-sequencing-rule UPDATE — see
-    -- the INSERT trigger comment for the rationale (a draft sr that
-    -- shares its PE with a published peer must not flip the PE to
-    -- draft). Identity columns DO mirror so editing name/code from
-    -- the admin UI continues to reach the lawyer-visible label.
-    UPDATE paliad.procedural_events
-       SET code                  = v_code,
-           name                  = NEW.name,
-           name_en               = NEW.name_en,
-           description           = NEW.description,
-           event_kind            = NEW.event_type,
-           primary_party_default = NEW.primary_party,
-           legal_source_id       = v_legal_source_id,
-           concept_id            = NEW.concept_id,
-           updated_at            = now()
-     WHERE id = (SELECT procedural_event_id
-                   FROM paliad.sequencing_rules
-                  WHERE id = NEW.id);
-
-    -- Update sequencing_rules (1:1 by id).
-    UPDATE paliad.sequencing_rules
-       SET proceeding_type_id       = NEW.proceeding_type_id,
-           parent_id                = NEW.parent_id,
-           trigger_event_id         = NEW.trigger_event_id,
-           duration_value           = NEW.duration_value,
-           duration_unit            = NEW.duration_unit,
-           timing                   = NEW.timing,
-           alt_duration_value       = NEW.alt_duration_value,
-           alt_duration_unit        = NEW.alt_duration_unit,
-           alt_rule_code            = NEW.alt_rule_code,
-           anchor_alt               = NEW.anchor_alt,
-           combine_op               = NEW.combine_op,
-           condition_expr           = NEW.condition_expr,
-           primary_party            = NEW.primary_party,
-           sequence_order           = NEW.sequence_order,
-           is_spawn                 = NEW.is_spawn,
-           spawn_label              = NEW.spawn_label,
-           spawn_proceeding_type_id = NEW.spawn_proceeding_type_id,
-           is_bilateral             = NEW.is_bilateral,
-           is_court_set             = NEW.is_court_set,
-           priority                 = NEW.priority,
-           rule_code                = NEW.rule_code,
-           rule_codes               = NEW.rule_codes,
-           deadline_notes           = NEW.deadline_notes,
-           deadline_notes_en        = NEW.deadline_notes_en,
-           choices_offered          = NEW.choices_offered,
-           applies_to_target        = NEW.applies_to_target,
-           lifecycle_state          = NEW.lifecycle_state,
-           draft_of                 = NEW.draft_of,
-           published_at             = NEW.published_at,
-           is_active                = NEW.is_active,
-           updated_at               = now()
-     WHERE id = NEW.id;
-
-    RETURN NEW;
-END $fn$;
-
-CREATE TRIGGER deadline_rules_unified_update
-    INSTEAD OF UPDATE ON paliad.deadline_rules_unified
-    FOR EACH ROW EXECUTE FUNCTION paliad.deadline_rules_unified_update_trigger();
-
--- ---------------------------------------------------------------
--- 8. POST assertions.
--- ---------------------------------------------------------------
-
-DO $$
-DECLARE
-    v_snapshot_count   int;
-    v_view_count       int;
-    v_dr_table_exists  int;
-    v_rule_id_col      int;
-BEGIN
-    SELECT COUNT(*) INTO v_snapshot_count FROM paliad.deadline_rules_pre_140;
-    SELECT COUNT(*) INTO v_view_count     FROM paliad.deadline_rules_unified;
-    IF v_snapshot_count <> v_view_count THEN
-        RAISE EXCEPTION '[mig 140] FAILED POST: snapshot has % rows, view has % rows — drift between final state and snapshot',
-            v_snapshot_count, v_view_count;
-    END IF;
-
-    SELECT COUNT(*) INTO v_dr_table_exists
-      FROM information_schema.tables
-     WHERE table_schema = 'paliad' AND table_name = 'deadline_rules';
-    IF v_dr_table_exists > 0 THEN
-        RAISE EXCEPTION '[mig 140] FAILED POST: paliad.deadline_rules table still exists after DROP';
-    END IF;
-
-    SELECT COUNT(*) INTO v_rule_id_col
-      FROM information_schema.columns
-     WHERE table_schema = 'paliad' AND table_name = 'deadlines' AND column_name = 'rule_id';
-    IF v_rule_id_col > 0 THEN
-        RAISE EXCEPTION '[mig 140] FAILED POST: paliad.deadlines.rule_id column still exists after DROP';
-    END IF;
-
-    RAISE NOTICE '[mig 140] OK — deadline_rules dropped, snapshot=% rows, view=% rows, INSTEAD OF triggers active',
-        v_snapshot_count, v_view_count;
-END $$;

internal/handlers/submissions.go

@@ -200,7 +200,7 @@ func loadSubmissionCatalog(ctx context.Context, projectProceedingTypeID *int) ([
 		        pt.code                AS proceeding_code,
 		        pt.name                AS proceeding_name,
 		        pt.name_en             AS proceeding_name_en
-		   FROM paliad.deadline_rules_unified dr
+		   FROM paliad.deadline_rules dr
 		   JOIN paliad.proceeding_types pt ON pt.id = dr.proceeding_type_id
 		  WHERE dr.is_active = true
 		    AND dr.lifecycle_state = 'published'

internal/models/models.go

@@ -264,14 +264,7 @@ type Deadline struct {
 	OriginalDueDate *time.Time `db:"original_due_date" json:"original_due_date,omitempty"`
 	WarningDate     *time.Time `db:"warning_date"      json:"warning_date,omitempty"`
 	Source          string     `db:"source"            json:"source"`
-	// Slice B.4 (mig 140, t-paliad-305): paliad.deadlines.rule_id column
-	// dropped; the back-link now lives on `sequencing_rule_id` (FK to
-	// paliad.sequencing_rules). Same UUID values (sequencing_rules.id
-	// inherited deadline_rules.id during mig 136 backfill), so internal
-	// Go references to `RuleID` continue to carry the same semantic
-	// pointer. The JSON name stays `rule_id` for frontend backward-compat
-	// — B.5 will rename if/when frontend is updated.
-	RuleID          *uuid.UUID `db:"sequencing_rule_id" json:"rule_id,omitempty"`
+	RuleID          *uuid.UUID `db:"rule_id"           json:"rule_id,omitempty"`
 	// RuleCode is the legal citation ("RoP.023", "R.151") attached at
 	// save time — see migration 032. Free text by design; survives
 	// changes to paliad.deadline_rules and accepts citations from

internal/services/deadline_rule_service.go

@@ -55,13 +55,13 @@ func (s *DeadlineRuleService) List(ctx context.Context, proceedingTypeID *int) (
 	if proceedingTypeID != nil {
 		err = s.db.SelectContext(ctx, &rules,
 			`SELECT `+ruleColumns+`
-			   FROM paliad.deadline_rules_unified
+			   FROM paliad.deadline_rules
 			  WHERE proceeding_type_id = $1 AND is_active = true
 			  ORDER BY sequence_order`, *proceedingTypeID)
 	} else {
 		err = s.db.SelectContext(ctx, &rules,
 			`SELECT `+ruleColumns+`
-			   FROM paliad.deadline_rules_unified
+			   FROM paliad.deadline_rules
 			  WHERE is_active = true
 			  ORDER BY proceeding_type_id, sequence_order`)
 	}
@@ -100,7 +100,7 @@ func (s *DeadlineRuleService) hydrateConceptDefaultEventTypes(ctx context.Contex
 	}
 	query, args, err := sqlx.In(
 		`SELECT dr.id AS rule_id, j.event_type_id
-		   FROM paliad.deadline_rules_unified dr
+		   FROM paliad.deadline_rules dr
 		   JOIN paliad.proceeding_types pt ON pt.id = dr.proceeding_type_id
 		   JOIN paliad.deadline_concept_event_types j
 		         ON j.concept_id = dr.concept_id
@@ -152,7 +152,7 @@ func (s *DeadlineRuleService) GetRuleTree(ctx context.Context, proceedingTypeCod
 	var rules []models.DeadlineRule
 	if err := s.db.SelectContext(ctx, &rules,
 		`SELECT `+ruleColumns+`
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		  WHERE proceeding_type_id = $1 AND is_active = true
 		  ORDER BY sequence_order`, pt.ID); err != nil {
 		return nil, fmt.Errorf("list rules for %q: %w", proceedingTypeCode, err)
@@ -175,10 +175,10 @@ func (s *DeadlineRuleService) GetFullTimeline(ctx context.Context, proceedingTyp
 	var rules []models.DeadlineRule
 	err := s.db.SelectContext(ctx, &rules, `
 		WITH RECURSIVE tree AS (
-			SELECT * FROM paliad.deadline_rules_unified
+			SELECT * FROM paliad.deadline_rules
 			 WHERE proceeding_type_id = $1 AND parent_id IS NULL AND is_active = true
 			UNION ALL
-			SELECT dr.* FROM paliad.deadline_rules_unified dr
+			SELECT dr.* FROM paliad.deadline_rules dr
 			JOIN tree t ON dr.parent_id = t.id
 			WHERE dr.is_active = true
 		)
@@ -196,7 +196,7 @@ func (s *DeadlineRuleService) GetByIDs(ctx context.Context, ids []uuid.UUID) ([]
 	}
 	query, args, err := sqlx.In(
 		`SELECT `+ruleColumns+`
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		  WHERE id IN (?) AND is_active = true
 		  ORDER BY sequence_order`, ids)
 	if err != nil {
@@ -264,7 +264,7 @@ func (s *DeadlineRuleService) ListByTriggerEvent(ctx context.Context, triggerEve
 	var rules []models.DeadlineRule
 	if err := s.db.SelectContext(ctx, &rules,
 		`SELECT `+ruleColumns+`
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		  WHERE trigger_event_id = $1
 		    AND is_active = true
 		  ORDER BY sequence_order`, triggerEventID); err != nil {
@@ -292,7 +292,7 @@ func (s *DeadlineRuleService) ListByProceedingTypeIDs(ctx context.Context, ids [
 	}
 	query, args, err := sqlx.In(
 		`SELECT `+ruleColumns+`
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		  WHERE proceeding_type_id IN (?)
 		    AND is_active = true
 		  ORDER BY proceeding_type_id, sequence_order`, ids)
@@ -327,7 +327,7 @@ func (s *DeadlineRuleService) ListByConcept(ctx context.Context, conceptID uuid.
 	var rules []models.DeadlineRule
 	if err := s.db.SelectContext(ctx, &rules,
 		`SELECT `+ruleColumns+`
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		  WHERE concept_id = $1
 		    AND is_active = true
 		  ORDER BY proceeding_type_id NULLS LAST, sequence_order`, conceptID); err != nil {

internal/services/deadline_service.go

@@ -65,13 +65,8 @@ func (s *DeadlineService) pendingApprovalErr(ctx context.Context, deadlineID uui
 	return NewPendingApprovalError(rid, role)
 }
 
-// Slice B.4 (mig 140, t-paliad-305): rule_id column dropped from
-// paliad.deadlines. sequencing_rule_id holds the same UUID and is the
-// FK to paliad.sequencing_rules. SELECT-column lists below pull
-// sequencing_rule_id into the Deadline.RuleID field (db tag adjusted in
-// internal/models/models.go).
 const deadlineColumns = `id, project_id, title, description, due_date, original_due_date,
-	warning_date, source, sequencing_rule_id, rule_code, custom_rule_text, status, completed_at, caldav_uid, caldav_etag,
+	warning_date, source, rule_id, rule_code, custom_rule_text, status, completed_at, caldav_uid, caldav_etag,
 	notes, created_by, created_at, updated_at,
 	approval_status, pending_request_id, approved_by, approved_at`
 
@@ -277,7 +272,7 @@ func (s *DeadlineService) ListVisibleForUser(ctx context.Context, userID uuid.UU
 		       ar.requester_kind AS requester_kind
 		  FROM paliad.deadlines f
 		  JOIN paliad.projects p ON p.id = f.project_id
-		  LEFT JOIN paliad.deadline_rules_unified r ON r.id = f.sequencing_rule_id
+		  LEFT JOIN paliad.deadline_rules r ON r.id = f.rule_id
 		  LEFT JOIN paliad.approval_requests ar ON ar.id = f.pending_request_id
 		 WHERE ` + strings.Join(conds, " AND ") + `
 		 ORDER BY f.due_date ASC, f.created_at DESC`
@@ -544,11 +539,7 @@ func (s *DeadlineService) Update(ctx context.Context, userID, deadlineID uuid.UU
 		if input.RuleID != nil && input.CustomRuleText != nil {
 			return nil, fmt.Errorf("%w: rule_id and custom_rule_text are mutually exclusive", ErrInvalidInput)
 		}
-		// Slice B.4 (t-paliad-305): rule_id column dropped; the FK
-		// back-link now lives on sequencing_rule_id. Same UUID value.
-		// The procedural_event_id mirror is derived in
-		// syncDeadlineDualLinks below after the primary UPDATE lands.
-		appendSet("sequencing_rule_id", input.RuleID)
+		appendSet("rule_id", input.RuleID)
 		var customText *string
 		if input.CustomRuleText != nil {
 			trimmed := strings.TrimSpace(*input.CustomRuleText)
@@ -594,13 +585,13 @@ func (s *DeadlineService) Update(ctx context.Context, userID, deadlineID uuid.UU
 		if _, err := tx.ExecContext(ctx, query, args...); err != nil {
 			return nil, fmt.Errorf("update deadline: %w", err)
 		}
-		// Slice B.4 (mig 140, t-paliad-305): rule_id column gone;
-		// sequencing_rule_id holds the back-link. When the patch updated
-		// it (auto/custom swap from t-paliad-258), mirror the FK onto
-		// procedural_event_id so the joined view continues to resolve.
-		// Idempotent: no-op when sequencing_rule_id is unchanged.
+		// Slice B.2 dual-write (t-paliad-305): if rule_id was in the
+		// patch (auto/custom swap from t-paliad-258), the parallel
+		// procedural_event_id + sequencing_rule_id columns must follow.
+		// Call unconditionally — it's a single UPDATE keyed on
+		// deadlineID and a no-op when rule_id is unchanged.
 		if input.RuleSet {
-			if err := syncDeadlineProceduralEventID(ctx, tx, deadlineID); err != nil {
+			if err := syncDeadlineDualLinks(ctx, tx, deadlineID); err != nil {
 				return nil, err
 			}
 		}

internal/services/dual_write.go

@@ -1,50 +1,392 @@
-// Slice B.4 retirement of B.2 dual-write (t-paliad-305 / m/paliad#93).
+// Slice B.2 dual-write (t-paliad-305 / m/paliad#93) — keep paliad's
+// new tables (procedural_events / sequencing_rules / legal_sources) in
+// lock-step with the legacy paliad.deadline_rules table during the
+// dual-write window. Mig 136 (Slice B.1) created the new tables and
+// backfilled them once. This file keeps them in sync going forward.
 //
-// Mig 140 dropped paliad.deadline_rules and installed INSTEAD OF
-// triggers on paliad.deadline_rules_unified that route writes to
-// procedural_events + sequencing_rules + legal_sources. The legacy
-// dual-write helper (syncDualWriteFromDeadlineRule) and the drift-check
-// loop (CheckDualWriteDrift / StartDualWriteDriftCheckLoop) reference
-// paliad.deadline_rules, which no longer exists — they would crash on
-// first call if kept.
+// Contract:
 //
-// Survivor: syncDeadlineProceduralEventID — keeps paliad.deadlines's
-// new procedural_event_id column in sync with sequencing_rule_id after
-// any UPDATE that touched the latter. Still useful as a "derive from
-// canonical pointer" helper.
+//   - Every RuleEditorService method that mutates paliad.deadline_rules
+//     calls syncDualWriteFromDeadlineRule(ctx, tx, id) inside the same
+//     transaction, AFTER the deadline_rules write, BEFORE tx.Commit.
+//   - The sync is idempotent (INSERT … ON CONFLICT … DO UPDATE) so the
+//     same call works for Create (new row), UpdateDraft (existing row),
+//     CloneAsDraft (new row referencing an old row), Publish (lifecycle
+//     flip), Archive/Restore (lifecycle flip), and the published-peer
+//     archive that Publish performs as a cascade.
+//   - The sync re-derives the new-table state from paliad.deadline_rules
+//     in pure SQL — no struct mapping in Go. The legacy table stays the
+//     source of truth during B.2 (B.3 flips reads, B.4 drops it).
+//   - Read paths still read deadline_rules in B.2. The new tables are a
+//     parallel projection kept consistent for B.3's read cutover; they
+//     are not yet authoritative.
 //
-// The DualWriteDriftReport struct + HasDrift method are retired with
-// the loop they served.
-
+// Why a per-row sync instead of a global trigger:
+//
+//   - The deadline_rules audit trigger (mig 079) reads paliad.audit_reason
+//     to record the rationale on every change. Putting the new-table
+//     write in the same TX preserves that auditability — set_config is
+//     transactional and the new writes share the same reason.
+//   - A Postgres-side AFTER UPDATE trigger on deadline_rules would also
+//     work but it's harder to test in isolation and harder to revert
+//     when B.4 drops the source table. A Go-side sync is reversible
+//     with a code revert; an SQL trigger needs a follow-up migration.
+//
+// The drift-check job (CheckDualWriteDrift below) runs daily and
+// alerts on mismatches. If the sync ever silently misses a row, the
+// drift check surfaces it inside one day.
+//
+// See docs/design-procedural-events-model-2026-05-25.md §5.2 (dual-write
+// phase) and docs/design-procedural-events-b0-findings-2026-05-26.md §7.
 package services
 
 import (
 	"context"
 	"fmt"
+	"log"
+	"time"
 
 	"github.com/google/uuid"
 	"github.com/jmoiron/sqlx"
 )
 
-// syncDeadlineProceduralEventID mirrors paliad.deadlines.sequencing_rule_id
-// onto procedural_event_id. Call this within an open transaction AFTER
-// any UPDATE that mutates paliad.deadlines.sequencing_rule_id (today's
-// callers: DeadlineService.Update on the RuleSet branch, and the
-// RuleEditorService orphan-resolve path which sets both columns in one
-// statement so doesn't need this helper).
+// syncDualWriteFromDeadlineRule re-projects the deadline_rules row with
+// the given id into legal_sources + procedural_events + sequencing_rules.
+// Runs three UPSERT statements in the open transaction.
 //
-// Idempotent: NULL sequencing_rule_id collapses procedural_event_id to
-// NULL via the subquery returning NULL. Slice B.4 (t-paliad-305).
-func syncDeadlineProceduralEventID(ctx context.Context, tx *sqlx.Tx, deadlineID uuid.UUID) error {
+// Synthetic-code rule (for rows where deadline_rules.submission_code is
+// NULL) mirrors mig 136's backfill: 'null.' || first 8 hex chars of the
+// uuid (dashes stripped). This must stay byte-identical to the mig 136
+// expression or the lookup join inside the sequencing_rules UPSERT
+// misses.
+func syncDualWriteFromDeadlineRule(ctx context.Context, tx *sqlx.Tx, id uuid.UUID) error {
+	// 1. legal_sources — UPSERT the citation (no-op if already present).
+	//    jurisdiction is parsed from the first dot-separated segment;
+	//    'other' on empty (paranoid fallback, no live rows hit it).
+	if _, err := tx.ExecContext(ctx, `
+		INSERT INTO paliad.legal_sources (citation, jurisdiction)
+		SELECT dr.legal_source,
+		       COALESCE(NULLIF(split_part(dr.legal_source, '.', 1), ''), 'other')
+		  FROM paliad.deadline_rules dr
+		 WHERE dr.id = $1 AND dr.legal_source IS NOT NULL
+		ON CONFLICT (citation) DO NOTHING`, id); err != nil {
+		return fmt.Errorf("dual-write legal_sources for rule %s: %w", id, err)
+	}
+
+	// 2. procedural_events — UPSERT keyed by code. The code is the
+	//    submission_code if present, else the synthetic 'null.<8hex>'
+	//    minted from the deadline_rules row's id (matches mig 136).
+	//    legal_source_id is resolved by JOIN on legal_sources.citation
+	//    (NULL when the rule has no legal_source).
+	if _, err := tx.ExecContext(ctx, `
+		INSERT INTO paliad.procedural_events
+		    (code, name, name_en, description, event_kind,
+		     primary_party_default, legal_source_id, concept_id,
+		     lifecycle_state, published_at, is_active)
+		SELECT
+		    COALESCE(dr.submission_code,
+		             'null.' || substring(replace(dr.id::text, '-', ''), 1, 8)),
+		    dr.name, dr.name_en, dr.description, dr.event_type,
+		    dr.primary_party, ls.id, dr.concept_id,
+		    dr.lifecycle_state, dr.published_at, dr.is_active
+		  FROM paliad.deadline_rules dr
+		  LEFT JOIN paliad.legal_sources ls ON ls.citation = dr.legal_source
+		 WHERE dr.id = $1
+		ON CONFLICT (code) DO UPDATE SET
+		    name                  = EXCLUDED.name,
+		    name_en               = EXCLUDED.name_en,
+		    description           = EXCLUDED.description,
+		    event_kind            = EXCLUDED.event_kind,
+		    primary_party_default = EXCLUDED.primary_party_default,
+		    legal_source_id       = EXCLUDED.legal_source_id,
+		    concept_id            = EXCLUDED.concept_id,
+		    lifecycle_state       = EXCLUDED.lifecycle_state,
+		    published_at          = EXCLUDED.published_at,
+		    is_active             = EXCLUDED.is_active,
+		    updated_at            = now()`, id); err != nil {
+		return fmt.Errorf("dual-write procedural_events for rule %s: %w", id, err)
+	}
+
+	// 3. sequencing_rules — UPSERT keyed by id (1:1 inheritance from
+	//    deadline_rules.id). procedural_event_id resolved by JOIN on
+	//    the (real or synthetic) code. All hat-3 mechanics columns copy
+	//    1:1 from the deadline_rules row's post-write state.
+	if _, err := tx.ExecContext(ctx, `
+		INSERT INTO paliad.sequencing_rules
+		    (id, procedural_event_id, proceeding_type_id, parent_id, trigger_event_id,
+		     duration_value, duration_unit, timing,
+		     alt_duration_value, alt_duration_unit, alt_rule_code, anchor_alt,
+		     combine_op, condition_expr, primary_party, sequence_order,
+		     is_spawn, spawn_label, spawn_proceeding_type_id,
+		     is_bilateral, is_court_set, priority,
+		     rule_code, rule_codes, deadline_notes, deadline_notes_en,
+		     choices_offered, applies_to_target,
+		     lifecycle_state, draft_of, published_at, is_active,
+		     created_at, updated_at)
+		SELECT
+		    dr.id, pe.id,
+		    dr.proceeding_type_id, dr.parent_id, dr.trigger_event_id,
+		    dr.duration_value, dr.duration_unit, dr.timing,
+		    dr.alt_duration_value, dr.alt_duration_unit, dr.alt_rule_code, dr.anchor_alt,
+		    dr.combine_op, dr.condition_expr, dr.primary_party, dr.sequence_order,
+		    dr.is_spawn, dr.spawn_label, dr.spawn_proceeding_type_id,
+		    dr.is_bilateral, dr.is_court_set, dr.priority,
+		    dr.rule_code, dr.rule_codes, dr.deadline_notes, dr.deadline_notes_en,
+		    dr.choices_offered, dr.applies_to_target,
+		    dr.lifecycle_state, dr.draft_of, dr.published_at, dr.is_active,
+		    dr.created_at, dr.updated_at
+		  FROM paliad.deadline_rules dr
+		  JOIN paliad.procedural_events pe
+		    ON pe.code = COALESCE(dr.submission_code,
+		                          'null.' || substring(replace(dr.id::text, '-', ''), 1, 8))
+		 WHERE dr.id = $1
+		ON CONFLICT (id) DO UPDATE SET
+		    procedural_event_id      = EXCLUDED.procedural_event_id,
+		    proceeding_type_id       = EXCLUDED.proceeding_type_id,
+		    parent_id                = EXCLUDED.parent_id,
+		    trigger_event_id         = EXCLUDED.trigger_event_id,
+		    duration_value           = EXCLUDED.duration_value,
+		    duration_unit            = EXCLUDED.duration_unit,
+		    timing                   = EXCLUDED.timing,
+		    alt_duration_value       = EXCLUDED.alt_duration_value,
+		    alt_duration_unit        = EXCLUDED.alt_duration_unit,
+		    alt_rule_code            = EXCLUDED.alt_rule_code,
+		    anchor_alt               = EXCLUDED.anchor_alt,
+		    combine_op               = EXCLUDED.combine_op,
+		    condition_expr           = EXCLUDED.condition_expr,
+		    primary_party            = EXCLUDED.primary_party,
+		    sequence_order           = EXCLUDED.sequence_order,
+		    is_spawn                 = EXCLUDED.is_spawn,
+		    spawn_label              = EXCLUDED.spawn_label,
+		    spawn_proceeding_type_id = EXCLUDED.spawn_proceeding_type_id,
+		    is_bilateral             = EXCLUDED.is_bilateral,
+		    is_court_set             = EXCLUDED.is_court_set,
+		    priority                 = EXCLUDED.priority,
+		    rule_code                = EXCLUDED.rule_code,
+		    rule_codes               = EXCLUDED.rule_codes,
+		    deadline_notes           = EXCLUDED.deadline_notes,
+		    deadline_notes_en        = EXCLUDED.deadline_notes_en,
+		    choices_offered          = EXCLUDED.choices_offered,
+		    applies_to_target        = EXCLUDED.applies_to_target,
+		    lifecycle_state          = EXCLUDED.lifecycle_state,
+		    draft_of                 = EXCLUDED.draft_of,
+		    published_at             = EXCLUDED.published_at,
+		    is_active                = EXCLUDED.is_active,
+		    updated_at               = now()`, id); err != nil {
+		return fmt.Errorf("dual-write sequencing_rules for rule %s: %w", id, err)
+	}
+
+	return nil
+}
+
+// syncDeadlineDualLinks mirrors a deadline's legacy rule_id back-link
+// onto the new procedural_event_id + sequencing_rule_id columns added
+// by mig 136. Call this within an open transaction AFTER any UPDATE
+// that mutates paliad.deadlines.rule_id (mig 122 introduced rule_id
+// as the deadline→rule FK; today's writers are DeadlineService.Update
+// and RuleEditorService.ResolveOrphan).
+//
+// Idempotent: NULL rule_id collapses both new columns to NULL by virtue
+// of the subquery returning NULL. Slice B.2 (t-paliad-305).
+func syncDeadlineDualLinks(ctx context.Context, tx *sqlx.Tx, deadlineID uuid.UUID) error {
 	if _, err := tx.ExecContext(ctx, `
 		UPDATE paliad.deadlines d
-		   SET procedural_event_id = (
+		   SET sequencing_rule_id  = d.rule_id,
+		       procedural_event_id = (
 		           SELECT sr.procedural_event_id
 		             FROM paliad.sequencing_rules sr
-		            WHERE sr.id = d.sequencing_rule_id
+		            WHERE sr.id = d.rule_id
 		       )
 		 WHERE d.id = $1`, deadlineID); err != nil {
-		return fmt.Errorf("sync deadline procedural_event_id for %s: %w", deadlineID, err)
+		return fmt.Errorf("sync deadline dual-links for %s: %w", deadlineID, err)
 	}
 	return nil
 }
+
+// DualWriteDriftReport summarises the comparison between the legacy
+// paliad.deadline_rules table and the new procedural_events /
+// sequencing_rules tables that B.2's dual-write is meant to keep in
+// sync. A zero-drift report (every count delta zero, every join clean)
+// is the steady state during the dual-write window; any non-zero field
+// is the signal that a write path either bypassed
+// syncDualWriteFromDeadlineRule or that an out-of-band mutation
+// happened (e.g. raw SQL run by an operator).
+type DualWriteDriftReport struct {
+	// Counts on the legacy and the projected side.
+	DeadlineRules    int `json:"deadline_rules"`
+	SequencingRules  int `json:"sequencing_rules"`
+	ProceduralEvents int `json:"procedural_events"`
+	LegalSources     int `json:"legal_sources"`
+
+	// Expected (from the legacy side) vs observed (on the new side).
+	ExpectedPE           int `json:"expected_procedural_events"`
+	ExpectedLegalSources int `json:"expected_legal_sources"`
+
+	// MissingSR — deadline_rules rows with no sequencing_rules row by id.
+	// OrphanedSR — sequencing_rules rows whose id doesn't exist in
+	// deadline_rules anymore (would only happen with a deletion path
+	// that bypasses dual-write).
+	MissingSR  int `json:"missing_sequencing_rules"`
+	OrphanedSR int `json:"orphaned_sequencing_rules"`
+
+	// MismatchedLifecycle — rows where deadline_rules.lifecycle_state
+	// disagrees with sequencing_rules.lifecycle_state. Should always be
+	// zero during dual-write.
+	MismatchedLifecycle int `json:"mismatched_lifecycle"`
+
+	// MismatchedActive — same shape, for is_active.
+	MismatchedActive int `json:"mismatched_active"`
+}
+
+// HasDrift returns true if any field signals divergence between the
+// legacy and projected sides. Used by the drift-check ticker to decide
+// whether to log at WARN (drift) or INFO (clean).
+func (r DualWriteDriftReport) HasDrift() bool {
+	if r.SequencingRules != r.DeadlineRules {
+		return true
+	}
+	if r.ProceduralEvents != r.ExpectedPE {
+		return true
+	}
+	if r.LegalSources != r.ExpectedLegalSources {
+		return true
+	}
+	if r.MissingSR != 0 || r.OrphanedSR != 0 {
+		return true
+	}
+	if r.MismatchedLifecycle != 0 || r.MismatchedActive != 0 {
+		return true
+	}
+	return false
+}
+
+// CheckDualWriteDrift compares the legacy paliad.deadline_rules table
+// against the parallel new tables maintained by Slice B.2's dual-write.
+// Returns a DualWriteDriftReport — caller decides what to do with
+// non-zero drift (log, page, fail healthcheck, etc.).
+//
+// Read-only. Safe to run against prod. Single query per metric so the
+// pool isn't held for a long time. No locks; tolerates concurrent
+// writes (counts may shift by one or two during the read, but a
+// persistent drift > 0 is the alarm signal).
+func CheckDualWriteDrift(ctx context.Context, conn *sqlx.DB) (*DualWriteDriftReport, error) {
+	var r DualWriteDriftReport
+
+	q := func(label, sql string, dst *int) error {
+		if err := conn.GetContext(ctx, dst, sql); err != nil {
+			return fmt.Errorf("drift-check %s: %w", label, err)
+		}
+		return nil
+	}
+
+	if err := q("dr_total", `SELECT COUNT(*) FROM paliad.deadline_rules`, &r.DeadlineRules); err != nil {
+		return nil, err
+	}
+	if err := q("sr_total", `SELECT COUNT(*) FROM paliad.sequencing_rules`, &r.SequencingRules); err != nil {
+		return nil, err
+	}
+	if err := q("pe_total", `SELECT COUNT(*) FROM paliad.procedural_events`, &r.ProceduralEvents); err != nil {
+		return nil, err
+	}
+	if err := q("ls_total", `SELECT COUNT(*) FROM paliad.legal_sources`, &r.LegalSources); err != nil {
+		return nil, err
+	}
+
+	if err := q("expected_pe", `
+		SELECT
+		  (SELECT COUNT(DISTINCT submission_code) FROM paliad.deadline_rules WHERE submission_code IS NOT NULL)
+		  +
+		  (SELECT COUNT(*) FROM paliad.deadline_rules WHERE submission_code IS NULL)
+	`, &r.ExpectedPE); err != nil {
+		return nil, err
+	}
+	if err := q("expected_ls",
+		`SELECT COUNT(DISTINCT legal_source) FROM paliad.deadline_rules WHERE legal_source IS NOT NULL`,
+		&r.ExpectedLegalSources); err != nil {
+		return nil, err
+	}
+
+	if err := q("missing_sr", `
+		SELECT COUNT(*) FROM paliad.deadline_rules dr
+		  LEFT JOIN paliad.sequencing_rules sr ON sr.id = dr.id
+		 WHERE sr.id IS NULL`, &r.MissingSR); err != nil {
+		return nil, err
+	}
+	if err := q("orphaned_sr", `
+		SELECT COUNT(*) FROM paliad.sequencing_rules sr
+		  LEFT JOIN paliad.deadline_rules dr ON dr.id = sr.id
+		 WHERE dr.id IS NULL`, &r.OrphanedSR); err != nil {
+		return nil, err
+	}
+
+	if err := q("mismatched_lifecycle", `
+		SELECT COUNT(*) FROM paliad.deadline_rules dr
+		  JOIN paliad.sequencing_rules sr ON sr.id = dr.id
+		 WHERE dr.lifecycle_state <> sr.lifecycle_state`, &r.MismatchedLifecycle); err != nil {
+		return nil, err
+	}
+	if err := q("mismatched_active", `
+		SELECT COUNT(*) FROM paliad.deadline_rules dr
+		  JOIN paliad.sequencing_rules sr ON sr.id = dr.id
+		 WHERE dr.is_active <> sr.is_active`, &r.MismatchedActive); err != nil {
+		return nil, err
+	}
+
+	return &r, nil
+}
+
+// StartDualWriteDriftCheckLoop runs CheckDualWriteDrift on a fixed
+// interval for the lifetime of ctx. A clean run logs at INFO level;
+// drift logs at WARN level with the full report payload. The first
+// check fires after `interval`, not immediately on Start — by the time
+// the ticker first fires the process has finished booting and the
+// initial backfill + dual-write writes have settled.
+//
+// Slice B.2 (t-paliad-305). interval should be short enough to surface
+// drift before the next deploy (so a broken dual-write doesn't sit
+// silent for a week) and long enough to avoid noise (the check holds
+// no locks but it does run nine SELECT COUNTs).
+//
+// Recommended interval: 6h. Override via the caller (cmd/server picks
+// the runtime value).
+func StartDualWriteDriftCheckLoop(ctx context.Context, conn *sqlx.DB, interval time.Duration) {
+	if interval <= 0 {
+		interval = 6 * time.Hour
+	}
+	go func() {
+		t := time.NewTicker(interval)
+		defer t.Stop()
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-t.C:
+				report, err := CheckDualWriteDrift(ctx, conn)
+				if err != nil {
+					log.Printf("dual-write drift-check: error: %v", err)
+					continue
+				}
+				if report.HasDrift() {
+					log.Printf("dual-write drift-check: DRIFT DETECTED — "+
+						"deadline_rules=%d sequencing_rules=%d "+
+						"procedural_events=%d (expected %d) "+
+						"legal_sources=%d (expected %d) "+
+						"missing_sr=%d orphaned_sr=%d "+
+						"mismatched_lifecycle=%d mismatched_active=%d",
+						report.DeadlineRules, report.SequencingRules,
+						report.ProceduralEvents, report.ExpectedPE,
+						report.LegalSources, report.ExpectedLegalSources,
+						report.MissingSR, report.OrphanedSR,
+						report.MismatchedLifecycle, report.MismatchedActive)
+				} else {
+					log.Printf("dual-write drift-check: OK — "+
+						"deadline_rules=%d sequencing_rules=%d "+
+						"procedural_events=%d legal_sources=%d",
+						report.DeadlineRules, report.SequencingRules,
+						report.ProceduralEvents, report.LegalSources)
+				}
+			}
+		}
+	}()
+}
+

internal/services/dual_write_test.go

@@ -202,11 +202,14 @@ func TestDualWrite_RuleEditorLifecycle(t *testing.T) {
 		t.Errorf("sequencing_rules.lifecycle_state after Archive: got %q, want %q", srLifecycleArchived, "archived")
 	}
 
-	// Slice B.4 (mig 140, t-paliad-305): the legacy paliad.deadline_rules
-	// table is gone and so is CheckDualWriteDrift — there's no parallel
-	// side to compare against. The INSTEAD OF triggers on the view
-	// guarantee parity by construction (single TX fan-out from one
-	// SQL write to three target tables).
+	// 5. Drift check should return zero drift right after the dance.
+	report, err := CheckDualWriteDrift(ctx, pool)
+	if err != nil {
+		t.Fatalf("CheckDualWriteDrift: %v", err)
+	}
+	if report.HasDrift() {
+		t.Errorf("CheckDualWriteDrift unexpectedly flagged drift: %+v", report)
+	}
 }
 
 // TestDualWrite_SyntheticCodeForNullSubmission asserts that a rule

internal/services/event_deadline_service.go

@@ -168,7 +168,7 @@ func (s *EventDeadlineService) Calculate(ctx context.Context, triggerEventID int
 		       COALESCE(timing, 'after') AS timing,
 		       deadline_notes, deadline_notes_en, alt_duration_value, alt_duration_unit,
 		       combine_op, rule_codes
-		  FROM paliad.deadline_rules_unified
+		  FROM paliad.deadline_rules
 		 WHERE trigger_event_id = $1 AND is_active = true
 		 ORDER BY sequence_order`, triggerEventID)
 	if err != nil {

internal/services/export_service.go

@@ -1138,7 +1138,7 @@ func personalSheetQueries(actorID uuid.UUID) []sheetQuery {
 		},
 		{
 			SheetName: "ref__deadline_rules",
-			SQL:       `SELECT * FROM paliad.deadline_rules_unified ORDER BY id`,
+			SQL:       `SELECT * FROM paliad.deadline_rules ORDER BY id`,
 		},
 		{
 			SheetName: "ref__deadline_concepts",
@@ -1518,7 +1518,7 @@ SELECT 'partner_unit_default'::text AS source,
 		{SheetName: "ref__proceeding_types", SQL: `SELECT * FROM paliad.proceeding_types ORDER BY id`},
 		{SheetName: "ref__event_types", SQL: `SELECT * FROM paliad.event_types ORDER BY id`},
 		{SheetName: "ref__event_categories", SQL: `SELECT * FROM paliad.event_categories ORDER BY id`},
-		{SheetName: "ref__deadline_rules", SQL: `SELECT * FROM paliad.deadline_rules_unified ORDER BY id`},
+		{SheetName: "ref__deadline_rules", SQL: `SELECT * FROM paliad.deadline_rules ORDER BY id`},
 		{SheetName: "ref__deadline_concepts", SQL: `SELECT * FROM paliad.deadline_concepts ORDER BY id`},
 		{SheetName: "ref__courts", SQL: `SELECT * FROM paliad.courts ORDER BY id`},
 		{SheetName: "ref__countries", SQL: `SELECT * FROM paliad.countries ORDER BY code`},
@@ -1563,7 +1563,7 @@ SELECT 'partner_unit_default'::text AS source,
 func orgSheetQueries() []sheetQuery {
 	return []sheetQuery{
 		// --- entity sheets (alphabetical) ---
-		{SheetName: "appointment_caldav_targets", SQL: `SELECT * FROM paliad.appointment_caldav_targets ORDER BY appointment_id, binding_id`},
+		{SheetName: "appointment_caldav_targets", SQL: `SELECT * FROM paliad.appointment_caldav_targets ORDER BY appointment_id, calendar_binding_id`},
 		{SheetName: "appointments", SQL: `SELECT * FROM paliad.appointments ORDER BY id`},
 		{SheetName: "approval_policies", SQL: `SELECT * FROM paliad.approval_policies ORDER BY id`},
 		{SheetName: "approval_requests", SQL: `SELECT * FROM paliad.approval_requests ORDER BY id`},
@@ -1621,7 +1621,7 @@ func orgSheetQueries() []sheetQuery {
 		{SheetName: "ref__deadline_concept_event_types", SQL: `SELECT * FROM paliad.deadline_concept_event_types ORDER BY concept_id, event_type_id`},
 		{SheetName: "ref__deadline_concepts", SQL: `SELECT * FROM paliad.deadline_concepts ORDER BY id`},
 		{SheetName: "ref__deadline_event_types", SQL: `SELECT * FROM paliad.deadline_event_types ORDER BY rule_id, event_type_id`},
-		{SheetName: "ref__deadline_rules", SQL: `SELECT * FROM paliad.deadline_rules_unified ORDER BY id`},
+		{SheetName: "ref__deadline_rules", SQL: `SELECT * FROM paliad.deadline_rules ORDER BY id`},
 		{SheetName: "ref__event_categories", SQL: `SELECT * FROM paliad.event_categories ORDER BY id`},
 		{SheetName: "ref__event_category_concepts", SQL: `SELECT * FROM paliad.event_category_concepts ORDER BY category_id, concept_id`},
 		{SheetName: "ref__event_types", SQL: `SELECT * FROM paliad.event_types ORDER BY id`},

internal/services/fristenrechner.go

@@ -169,7 +169,7 @@ func (c *paliadCatalog) LoadRuleByID(ctx context.Context, ruleID string) (*model
 	var rule models.DeadlineRule
 	err := c.rules.db.GetContext(ctx, &rule,
 		`SELECT `+ruleColumns+`
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		  WHERE id = $1 AND is_active = true`, ruleID)
 	if errors.Is(err, sql.ErrNoRows) {
 		return nil, lp.ErrUnknownRule
@@ -200,7 +200,7 @@ func (c *paliadCatalog) LoadRuleByCode(ctx context.Context, proceedingCode, subm
 	var rule models.DeadlineRule
 	err = c.rules.db.GetContext(ctx, &rule,
 		`SELECT `+ruleColumns+`
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		  WHERE proceeding_type_id = $1 AND submission_code = $2 AND is_active = true`,
 		pt.ID, submissionCode)
 	if errors.Is(err, sql.ErrNoRows) {
@@ -311,7 +311,7 @@ func (c *paliadCatalog) LookupEvents(ctx context.Context, axes lp.EventLookupAxe
 		       pt.trigger_event_label_de AS pt_trigger_event_label_de,
 		       pt.trigger_event_label_en AS pt_trigger_event_label_en,
 		       pt.appeal_target AS pt_appeal_target
-		  FROM paliad.deadline_rules_unified dr
+		  FROM paliad.deadline_rules dr
 		  JOIN paliad.proceeding_types pt ON pt.id = dr.proceeding_type_id
 		 WHERE ` + strings.Join(where, "\n   AND ") + `
 		 ORDER BY dr.proceeding_type_id, dr.sequence_order`

internal/services/projection_service.go

@@ -1767,7 +1767,7 @@ func (s *ProjectionService) lookupRuleBySubmissionCode(ctx context.Context, ptID
 	var rule models.DeadlineRule
 	err := s.db.GetContext(ctx, &rule,
 		`SELECT `+ruleColumns+`
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		  WHERE proceeding_type_id = $1 AND submission_code = $2 AND is_active = true`,
 		ptID, code)
 	if errors.Is(err, sql.ErrNoRows) {
@@ -1784,7 +1784,7 @@ func (s *ProjectionService) lookupRuleByID(ctx context.Context, id uuid.UUID) (*
 	var rule models.DeadlineRule
 	err := s.db.GetContext(ctx, &rule,
 		`SELECT `+ruleColumns+`
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		  WHERE id = $1`, id)
 	if err != nil {
 		return nil, fmt.Errorf("lookup rule by id: %w", err)
@@ -1805,7 +1805,7 @@ func (s *ProjectionService) parentHasAnchoredActual(ctx context.Context, project
 	err := s.db.GetContext(ctx, &count, `
 		SELECT COUNT(*) FROM (
 			SELECT 1 FROM paliad.deadlines
-			 WHERE project_id = $1 AND sequencing_rule_id = $2
+			 WHERE project_id = $1 AND rule_id = $2
 			   AND (completed_at IS NOT NULL
 			        OR status = 'completed'
 			        OR source = 'anchor')
@@ -1843,7 +1843,7 @@ func (s *ProjectionService) upsertAnchorDeadline(ctx context.Context, userID, pr
 	var existingID uuid.UUID
 	err := s.db.GetContext(ctx, &existingID,
 		`SELECT id FROM paliad.deadlines
-		  WHERE project_id = $1 AND sequencing_rule_id = $2
+		  WHERE project_id = $1 AND rule_id = $2
 		  ORDER BY created_at ASC
 		  LIMIT 1`, projectID, rule.ID)
 	switch {

internal/services/rule_editor_orphans.go

@@ -117,7 +117,7 @@ func (s *RuleEditorService) ListOrphans(ctx context.Context) ([]Orphan, error) {
 		}
 		if err := s.db.SelectContext(ctx, &cs, `
 			SELECT id, rule_code, name, name_en
-			  FROM paliad.deadline_rules_unified
+			  FROM paliad.deadline_rules
 			 WHERE id = ANY($1::uuid[])`, pq.Array(uuidStrs)); err != nil {
 			return nil, fmt.Errorf("list orphan candidate rules: %w", err)
 		}
@@ -212,21 +212,20 @@ func (s *RuleEditorService) ResolveOrphan(ctx context.Context, orphanID uuid.UUI
 	}
 
 	now := time.Now().UTC()
-	// Slice B.4 (mig 140, t-paliad-305): paliad.deadlines.rule_id column
-	// dropped. Back-link lives on sequencing_rule_id (same UUIDs as
-	// before — sr.id inherited dr.id at mig 136 backfill).
-	// procedural_event_id is derived from the same sequencing_rules row.
 	if _, err := tx.ExecContext(ctx,
-		`UPDATE paliad.deadlines d
-		    SET sequencing_rule_id  = $1,
-		        procedural_event_id = (SELECT procedural_event_id
-		                                  FROM paliad.sequencing_rules
-		                                 WHERE id = $1),
-		        updated_at          = $2
-		  WHERE d.id = $3`,
+		`UPDATE paliad.deadlines
+		    SET rule_id    = $1,
+		        updated_at = $2
+		  WHERE id = $3`,
 		ruleID, now, oc.DeadlineID,
 	); err != nil {
-		return fmt.Errorf("set deadline sequencing_rule_id: %w", err)
+		return fmt.Errorf("set deadline rule_id: %w", err)
+	}
+	// Slice B.2 dual-write (t-paliad-305): mirror the new linkage onto
+	// the parallel deadlines.procedural_event_id + sequencing_rule_id
+	// columns so they don't drift from rule_id.
+	if err := syncDeadlineDualLinks(ctx, tx, oc.DeadlineID); err != nil {
+		return err
 	}
 	if _, err := tx.ExecContext(ctx,
 		`UPDATE paliad.deadline_rule_backfill_orphans

internal/services/rule_editor_service.go

@@ -178,7 +178,7 @@ func (s *RuleEditorService) Create(ctx context.Context, input CreateRuleInput, r
 	// here writes the live shape only — priority + condition_expr
 	// + is_court_set are the new gates.
 	if _, err := tx.ExecContext(ctx,
-		`INSERT INTO paliad.deadline_rules_unified
+		`INSERT INTO paliad.deadline_rules
 		    (id, proceeding_type_id, trigger_event_id, parent_id, concept_id, submission_code,
 		     name, name_en, description, primary_party, event_type,
 		     duration_value, duration_unit, timing,
@@ -209,11 +209,13 @@ func (s *RuleEditorService) Create(ctx context.Context, input CreateRuleInput, r
 		return nil, fmt.Errorf("insert rule: %w", err)
 	}
 
-	// Slice B.4 (mig 140, t-paliad-305): write routes through the
-	// INSTEAD OF triggers on paliad.deadline_rules_unified, which fan
-	// out into legal_sources + procedural_events + sequencing_rules.
-	// No Go-side mirror call needed — the INSERT above already landed
-	// the parallel rows.
+	// Slice B.2 dual-write (t-paliad-305): project the new row into
+	// legal_sources / procedural_events / sequencing_rules in the same
+	// transaction so the parallel tables stay in lock-step with
+	// deadline_rules through the B.3 read-cutover window.
+	if err := syncDualWriteFromDeadlineRule(ctx, tx, id); err != nil {
+		return nil, err
+	}
 
 	if err := tx.Commit(); err != nil {
 		return nil, fmt.Errorf("commit create: %w", err)
@@ -277,13 +279,15 @@ func (s *RuleEditorService) UpdateDraft(ctx context.Context, id uuid.UUID, patch
 	args = append(args, time.Now().UTC())
 	args = append(args, id)
 	q := fmt.Sprintf(
-		`UPDATE paliad.deadline_rules_unified SET %s WHERE id = $%d AND lifecycle_state = 'draft'`,
+		`UPDATE paliad.deadline_rules SET %s WHERE id = $%d AND lifecycle_state = 'draft'`,
 		strings.Join(sets, ", "), len(args))
 	if _, err := tx.ExecContext(ctx, q, args...); err != nil {
 		return nil, fmt.Errorf("update rule draft: %w", err)
 	}
-	// Slice B.4 (mig 140, t-paliad-305): INSTEAD OF trigger handles the
-	// new-table writes — the UPDATE above is already fan-out.
+	// Slice B.2 dual-write (t-paliad-305).
+	if err := syncDualWriteFromDeadlineRule(ctx, tx, id); err != nil {
+		return nil, err
+	}
 	if err := tx.Commit(); err != nil {
 		return nil, fmt.Errorf("commit update: %w", err)
 	}
@@ -317,7 +321,7 @@ func (s *RuleEditorService) CloneAsDraft(ctx context.Context, id uuid.UUID, reas
 
 	newID := uuid.New()
 	if _, err := tx.ExecContext(ctx,
-		`INSERT INTO paliad.deadline_rules_unified
+		`INSERT INTO paliad.deadline_rules
 		    (id, proceeding_type_id, trigger_event_id, parent_id, concept_id, submission_code,
 		     name, name_en, description, primary_party, event_type,
 		     duration_value, duration_unit, timing,
@@ -338,16 +342,20 @@ func (s *RuleEditorService) CloneAsDraft(ctx context.Context, id uuid.UUID, reas
 		        is_active,
 		        'draft', $2, NULL,
 		        now(), now()
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		  WHERE id = $2`,
 		newID, id,
 	); err != nil {
 		return nil, fmt.Errorf("clone rule as draft: %w", err)
 	}
-	// Slice B.4 (mig 140, t-paliad-305): INSTEAD OF INSERT trigger
-	// mints the synthetic 'null.<8hex>' code when submission_code is
-	// NULL (matching mig 136 + the legacy dual-write helper's
-	// expression).
+	// Slice B.2 dual-write (t-paliad-305): new draft gets its own
+	// procedural_events + sequencing_rules row. The synthetic-code
+	// branch fires here when the source rule had NULL submission_code
+	// (the clone inherits the NULL and mints a fresh 'null.<8hex>'
+	// derived from newID).
+	if err := syncDualWriteFromDeadlineRule(ctx, tx, newID); err != nil {
+		return nil, err
+	}
 	if err := tx.Commit(); err != nil {
 		return nil, fmt.Errorf("commit clone: %w", err)
 	}
@@ -381,7 +389,7 @@ func (s *RuleEditorService) Publish(ctx context.Context, id uuid.UUID, reason st
 
 	now := time.Now().UTC()
 	if _, err := tx.ExecContext(ctx,
-		`UPDATE paliad.deadline_rules_unified
+		`UPDATE paliad.deadline_rules
 		    SET lifecycle_state = 'published',
 		        published_at = $1,
 		        updated_at   = $1
@@ -394,7 +402,7 @@ func (s *RuleEditorService) Publish(ctx context.Context, id uuid.UUID, reason st
 	// Archive the peer this draft was cloned from, if any.
 	if current.DraftOf != nil {
 		if _, err := tx.ExecContext(ctx,
-			`UPDATE paliad.deadline_rules_unified
+			`UPDATE paliad.deadline_rules
 			    SET lifecycle_state = 'archived',
 			        updated_at      = $1
 			  WHERE id = $2 AND lifecycle_state = 'published'`,
@@ -404,9 +412,17 @@ func (s *RuleEditorService) Publish(ctx context.Context, id uuid.UUID, reason st
 		}
 	}
 
-	// Slice B.4 (mig 140, t-paliad-305): both UPDATEs above route via
-	// the INSTEAD OF UPDATE trigger, which mirrors the lifecycle flip
-	// onto procedural_events + sequencing_rules in the same TX.
+	// Slice B.2 dual-write (t-paliad-305): sync both sides — the newly
+	// published draft AND the cloned-from peer that just flipped to
+	// archived (if any).
+	if err := syncDualWriteFromDeadlineRule(ctx, tx, id); err != nil {
+		return nil, err
+	}
+	if current.DraftOf != nil {
+		if err := syncDualWriteFromDeadlineRule(ctx, tx, *current.DraftOf); err != nil {
+			return nil, err
+		}
+	}
 
 	if err := tx.Commit(); err != nil {
 		return nil, fmt.Errorf("commit publish: %w", err)
@@ -455,7 +471,7 @@ func (s *RuleEditorService) flipLifecycle(ctx context.Context, id uuid.UUID, tar
 	// timestamp helps audit reads ("when was this rule first live?").
 	if target == "published" {
 		if _, err := tx.ExecContext(ctx,
-			`UPDATE paliad.deadline_rules_unified
+			`UPDATE paliad.deadline_rules
 			    SET lifecycle_state = $1,
 			        published_at    = COALESCE(published_at, $2),
 			        updated_at      = $2
@@ -466,7 +482,7 @@ func (s *RuleEditorService) flipLifecycle(ctx context.Context, id uuid.UUID, tar
 		}
 	} else {
 		if _, err := tx.ExecContext(ctx,
-			`UPDATE paliad.deadline_rules_unified
+			`UPDATE paliad.deadline_rules
 			    SET lifecycle_state = $1, updated_at = $2
 			  WHERE id = $3`,
 			target, now, id,
@@ -475,8 +491,11 @@ func (s *RuleEditorService) flipLifecycle(ctx context.Context, id uuid.UUID, tar
 		}
 	}
 
-	// Slice B.4 (mig 140, t-paliad-305): INSTEAD OF UPDATE trigger
-	// mirrors the lifecycle flip onto sr + pe.
+	// Slice B.2 dual-write (t-paliad-305): mirror the lifecycle flip
+	// onto sequencing_rules + procedural_events.
+	if err := syncDualWriteFromDeadlineRule(ctx, tx, id); err != nil {
+		return nil, err
+	}
 
 	if err := tx.Commit(); err != nil {
 		return nil, fmt.Errorf("commit flip: %w", err)
@@ -617,7 +636,7 @@ func (s *RuleEditorService) ListRules(ctx context.Context, f ListRulesFilter) ([
 		where = "WHERE " + strings.Join(conds, " AND ")
 	}
 	query := `SELECT ` + ruleColumns + `
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		   ` + where + `
 		  ORDER BY proceeding_type_id NULLS LAST, sequence_order
 		  LIMIT ` + addArg(f.Limit) + ` OFFSET ` + addArg(f.Offset)
@@ -637,7 +656,7 @@ func (s *RuleEditorService) GetByID(ctx context.Context, id uuid.UUID) (*models.
 func (s *RuleEditorService) getByID(ctx context.Context, id uuid.UUID) (*models.DeadlineRule, error) {
 	var r models.DeadlineRule
 	err := s.db.GetContext(ctx, &r,
-		`SELECT `+ruleColumns+` FROM paliad.deadline_rules_unified WHERE id = $1`, id)
+		`SELECT `+ruleColumns+` FROM paliad.deadline_rules WHERE id = $1`, id)
 	if errors.Is(err, sql.ErrNoRows) {
 		return nil, ErrRuleNotFound
 	}
@@ -696,7 +715,7 @@ func (s *RuleEditorService) validateSpawnNoCycle(ctx context.Context, ruleID *uu
 		visited[current] = true
 		var nexts []sql.NullInt64
 		q := `SELECT DISTINCT spawn_proceeding_type_id::bigint
-		        FROM paliad.deadline_rules_unified
+		        FROM paliad.deadline_rules
 		       WHERE proceeding_type_id = $1
 		         AND is_spawn = true
 		         AND spawn_proceeding_type_id IS NOT NULL

internal/services/submission_vars.go

@@ -243,7 +243,7 @@ func (s *SubmissionVarsService) loadPublishedRule(ctx context.Context, submissio
 	var rule models.DeadlineRule
 	err := s.db.GetContext(ctx, &rule,
 		`SELECT `+ruleColumns+`
-		   FROM paliad.deadline_rules_unified
+		   FROM paliad.deadline_rules
 		  WHERE submission_code = $1
 		    AND lifecycle_state = 'published'
 		    AND is_active = true
@@ -289,12 +289,12 @@ func (s *SubmissionVarsService) nextOpenDeadline(ctx context.Context, projectID,
 	var d models.Deadline
 	err := s.db.GetContext(ctx, &d,
 		`SELECT id, project_id, title, description, due_date, original_due_date,
-		        warning_date, source, sequencing_rule_id, rule_code, status, completed_at,
+		        warning_date, source, rule_id, rule_code, status, completed_at,
 		        caldav_uid, caldav_etag, notes, created_by, created_at, updated_at,
 		        approval_status, pending_request_id, approved_by, approved_at
 		   FROM paliad.deadlines
 		  WHERE project_id = $1
-		    AND sequencing_rule_id = $2
+		    AND rule_id = $2
 		    AND status = 'pending'
 		  ORDER BY due_date ASC
 		  LIMIT 1`, projectID, ruleID)