feat(fristenrechner): Step 2 third card "Verfahrensablauf einsehen"

t-paliad-168 deliverable 1. Adds a discoverable browse-/learn-mode
entry to the determinator alongside "Etwas einreichen" / "Etwas ist
passiert". Click drops straight into Pathway A's proceeding-tile
picker (navigateToPathway("a")).

The save-to-project CTA disables itself in this mode — extends
isAdhocMode() to also return true when no Step 1 context is set,
mirroring the existing ad-hoc explore behaviour.

i18n keys: deadlines.step2.browse.title / .desc (DE + EN).

frontend/src/client/fristenrechner.ts

@@ -2490,8 +2490,12 @@ function writeStep1ContextToURL(ctx: Step1Context, replace = false) {
 
 // isAdhocMode is read by the save-to-project CTA — ad-hoc has no
 // project to save against, so the CTA disables and renders a hint.
+// t-paliad-168: also true when no Step 1 context is set at all (the
+// "Verfahrensablauf einsehen" / sidebar deep-link browse path opens
+// Pathway A without an Akte). In both cases the user has no project
+// to save against; the CTA renders disabled with the same hint.
 function isAdhocMode(): boolean {
-  return currentStep1Context.kind === "adhoc";
+  return currentStep1Context.kind === "adhoc" || currentStep1Context.kind === "none";
 }
 
 function adhocSummaryLabel(forum: AdhocForum): string {
@@ -2705,6 +2709,12 @@ function initPathwayFork() {
   document.getElementById("fristen-step2-happened")?.addEventListener("click", () => {
     navigateToPathway("b", "tree");
   });
+  // t-paliad-168 — Verfahrensablauf einsehen (browse / learn). Drops
+  // straight into Pathway A's proceeding-tile picker. The save CTA
+  // disables itself in this mode (see isBrowseOrAdhocMode below).
+  document.getElementById("fristen-step2-browse")?.addEventListener("click", () => {
+    navigateToPathway("a");
+  });
 
   // Step 3a cards — File / Draft / Enter. File drops into the existing
   // Pathway A wizard; Enter routes to the manual-create form;

frontend/src/client/i18n.ts

@@ -21,6 +21,7 @@ const translations: Record<Lang, Record<string, string>> = {
     "nav.home": "Home",
     "nav.kostenrechner": "Kostenrechner",
     "nav.fristenrechner": "Fristenrechner",
+    "nav.verfahrensablauf": "Verfahrensablauf",
     "nav.downloads": "Downloads",
     "nav.links": "Links",
     "nav.glossar": "Glossar",
@@ -263,6 +264,8 @@ const translations: Record<Lang, Record<string, string>> = {
     "deadlines.step2.file.desc": "Outgoing — eine Frist tritt aus eigener Handlung ein.",
     "deadlines.step2.happened.title": "Etwas ist passiert",
     "deadlines.step2.happened.desc": "Incoming — ein Ereignis hat eine Frist ausgelöst.",
+    "deadlines.step2.browse.title": "Verfahrensablauf einsehen",
+    "deadlines.step2.browse.desc": "Browse / Learn — sehen, was wann passiert. Keine Frist eintragen.",
     "deadlines.save.cta.adhoc.hint": "Ad-hoc — kein Projekt, kein Speichern",
     "deadlines.step3a.heading": "Was möchten Sie einreichen?",
     "deadlines.step3a.back": "zurück zur Auswahl",
@@ -2233,6 +2236,7 @@ const translations: Record<Lang, Record<string, string>> = {
     "nav.home": "Home",
     "nav.kostenrechner": "Cost Calculator",
     "nav.fristenrechner": "Deadline Calculator",
+    "nav.verfahrensablauf": "Procedure Roadmap",
     "nav.downloads": "Downloads",
     "nav.links": "Links",
     "nav.glossar": "Glossary",
@@ -2472,6 +2476,8 @@ const translations: Record<Lang, Record<string, string>> = {
     "deadlines.step2.file.desc": "Outgoing — your action triggers a deadline.",
     "deadlines.step2.happened.title": "Something happened",
     "deadlines.step2.happened.desc": "Incoming — an event triggered a deadline.",
+    "deadlines.step2.browse.title": "Browse procedure roadmap",
+    "deadlines.step2.browse.desc": "Browse / Learn — see what happens when. No deadline entered.",
     "deadlines.save.cta.adhoc.hint": "Ad-hoc — no matter, no save",
     "deadlines.step3a.heading": "What do you want to file?",
     "deadlines.step3a.back": "back to selection",

frontend/src/fristenrechner.tsx

@@ -207,6 +207,20 @@ export function renderFristenrechner(): string {
                       Incoming — ein Ereignis hat eine Frist ausgelöst.
                     </span>
                   </button>
+                  {/* t-paliad-168 — third card: discoverable browse-/learn-mode
+                       entry. Drops directly into Pathway A (Verfahrensablauf
+                       wizard) with no save flow — mirrors the existing ad-hoc
+                       explore behaviour: timeline renders, save CTA stays
+                       disabled because there's no save intent. */}
+                  <button type="button" className="fristen-step2-card" data-action="browse" id="fristen-step2-browse">
+                    <span className="fristen-step2-card-icon" aria-hidden="true">&#128214;</span>
+                    <span className="fristen-step2-card-title" data-i18n="deadlines.step2.browse.title">
+                      Verfahrensablauf einsehen
+                    </span>
+                    <span className="fristen-step2-card-desc" data-i18n="deadlines.step2.browse.desc">
+                      Browse / Learn &mdash; sehen, was wann passiert. Keine Frist eintragen.
+                    </span>
+                  </button>
                 </div>
                 <div className="fristen-step2-shortcut">
                   <div className="fristen-pathway-fork-shortcut-label" data-i18n="deadlines.pathway.shortcut.label">