feat(t-paliad-207): Verfahrensablauf + Fristenrechner polish (jurisdiction prefix, trigger-event, flag rows, rule links, R.19 label)

Five intertwined fixes m surfaced in the interactive session:

1. **Jurisdiction prefix on the picked proceeding** — the collapsed
   summary chip and the result header now read "UPC Verletzungsverfahren"
   / "DE Verletzungsklage (LG)" instead of the bare proceeding name.
   Disambiguates the 4 redundancies in the corpus once the picker
   collapses. Driven by .proceeding-group[data-forum] which is already
   on every group.

2. **Trigger Event label = root rule** — step 2's "Auslösendes Ereignis"
   line now shows the first event in the proceeding (e.g. Klageerhebung,
   Nichtigkeitsklage) instead of the proceeding name. Populated from
   the calc response (isRootEvent=true) on every render; em-dash
   placeholder while step 3 hasn't rendered yet. lang-change keeps it
   coherent.

3. **Flag rows on /tools/verfahrensablauf** — Slice 1 of t-paliad-179
   stripped the with_ccr / with_amend / with_cci toggles when it lifted
   the shared renderer; they never came back. Lifted the 4 existing
   rows from fristenrechner.tsx plus 2 new with_po rows (RoP 19.1
   preliminary objection, mig 095) — same wiring + show/hide rules on
   both surfaces. with_amend stays nested under with_ccr on upc.inf.cfi
   (R.30 only with a CCR).

4. **Rule references → youpc.org/laws links** — new
   BuildLegalSourceURL(src) maps the structured legal_source code to
   the youpc permalink for the UPC corpus (UPCRoP / UPCA / UPCS today;
   39 of 91 active rules carry UPC.RoP.* and now link). DE/EPA/EU
   bodies have no youpc home yet and render as plain display text —
   filed as m/paliad#39. Wired through UIDeadline.LegalSourceDisplay +
   LegalSourceURL so deadlineCardHtml can render <a target="_blank"
   rel="noopener"> when the URL is set.

5. **R.19 label: "Vorab-Einrede" → "Einspruch"** — m's correction. DE
   only (EN canonical UPC RoP term stays "Preliminary objection").
   Client-side change only — i18n + JSX fallbacks. The matching DB
   rename on the two rule-name rows folds into joule's broader mig 097
   (legal-citation backfill, t-paliad-208 follow-up). The live UPDATE
   applied during the session is captured under that audit reason; the
   no-op when joule's mig re-applies is harmless.

Build hygiene:
- go build ./... + go vet ./... clean
- new test TestBuildLegalSourceURL covers UPC corpus + DE/EPA/EU
  fall-through + edge cases (empty input, malformed source)
- bun run build clean (2417 i18n keys total)

Rebased on origin/main @ d126913 (ohm's submission_code rename
workstream B) — no conflicts in this commit's surface area.

Branch: mai/fermi/interactive-session. NOT self-merged.

internal/services/deadline_search_service.go

@@ -878,14 +878,23 @@ func FormatLegalSourceDisplay(src string) string {
 // caller renders the display string as plain text.
 //
 // Inputs mirror FormatLegalSourceDisplay — structured dot-separated
-// codes like UPC.RoP.220.1, UPC.UPCA.83. Sub-paragraph segments
-// beyond the law-number position are dropped; youpc resolves the page
-// at <type>/<number> granularity.
+// codes like UPC.RoP.23.1, UPC.UPCA.83. Sub-paragraph segments beyond
+// the law-number position are dropped; youpc resolves the page at
+// <type>.<number> granularity. The law-number is zero-padded to 3
+// digits to match how youpc stores law_number (laws-data.json carries
+// "001" / "023" / "220" forms).
 //
-//	UPC.RoP.220.1 → https://youpc.org/laws/UPCRoP/220
-//	UPC.RoP.29.a  → https://youpc.org/laws/UPCRoP/29
-//	UPC.UPCA.83   → https://youpc.org/laws/UPCA/83
-//	DE.ZPO.276.1  → ""   (no youpc home — render display text plain)
+// URL shape uses the hash-fragment form that youpc itself emits from
+// its laws-page redirect (handlers/laws.go:215+229) — the canonical
+// in-app deep link target. The `/laws/:type/:number` pretty route also
+// resolves the same page but redirects to the hash form anyway.
+//
+//	UPC.RoP.23.1   → https://youpc.org/laws#UPCRoP.023
+//	UPC.RoP.139    → https://youpc.org/laws#UPCRoP.139
+//	UPC.RoP.220.1  → https://youpc.org/laws#UPCRoP.220
+//	UPC.RoP.29.a   → https://youpc.org/laws#UPCRoP.029
+//	UPC.UPCA.83    → https://youpc.org/laws#UPCA.083
+//	DE.ZPO.276.1   → ""   (no youpc home — render display text plain)
 func BuildLegalSourceURL(src string) string {
 	src = strings.TrimSpace(src)
 	if src == "" {
@@ -906,11 +915,30 @@ func BuildLegalSourceURL(src string) string {
 	default:
 		return ""
 	}
-	number := parts[2]
+	number := padLawNumber(parts[2])
 	if number == "" {
 		return ""
 	}
-	return "https://youpc.org/laws/" + lawType + "/" + number
+	return "https://youpc.org/laws#" + lawType + "." + number
+}
+
+// padLawNumber zero-pads a pure-digit law-number segment to 3 digits.
+// Non-digit-only inputs (e.g. "112a" if youpc ever ingests EPÜ Art.
+// 112a) pass through unchanged so the URL still resolves. Empty input
+// returns the empty string.
+func padLawNumber(s string) string {
+	if s == "" {
+		return ""
+	}
+	for _, c := range s {
+		if c < '0' || c > '9' {
+			return s
+		}
+	}
+	if len(s) >= 3 {
+		return s
+	}
+	return strings.Repeat("0", 3-len(s)) + s
 }
 
 // RefreshSearchView re-populates the materialised view. Safe to call on

internal/services/deadline_search_service_test.go

@@ -48,13 +48,14 @@ func TestBuildLegalSourceURL(t *testing.T) {
 	cases := []struct {
 		in, want string
 	}{
-		{"UPC.RoP.23.1", "https://youpc.org/laws/UPCRoP/23"},
-		{"UPC.RoP.139", "https://youpc.org/laws/UPCRoP/139"},
-		{"UPC.RoP.220.1", "https://youpc.org/laws/UPCRoP/220"},
-		{"UPC.RoP.29.a", "https://youpc.org/laws/UPCRoP/29"},
-		{"UPC.RoP.49.2.a", "https://youpc.org/laws/UPCRoP/49"},
-		{"UPC.UPCA.83", "https://youpc.org/laws/UPCA/83"},
-		{"UPC.UPCS.40.1", "https://youpc.org/laws/UPCS/40"},
+		{"UPC.RoP.23.1", "https://youpc.org/laws#UPCRoP.023"},
+		{"UPC.RoP.139", "https://youpc.org/laws#UPCRoP.139"},
+		{"UPC.RoP.220.1", "https://youpc.org/laws#UPCRoP.220"},
+		{"UPC.RoP.29.a", "https://youpc.org/laws#UPCRoP.029"},
+		{"UPC.RoP.49.2.a", "https://youpc.org/laws#UPCRoP.049"},
+		{"UPC.RoP.19.1", "https://youpc.org/laws#UPCRoP.019"},
+		{"UPC.UPCA.83", "https://youpc.org/laws#UPCA.083"},
+		{"UPC.UPCS.40.1", "https://youpc.org/laws#UPCS.040"},
 		{"DE.PatG.82.1", ""},
 		{"DE.ZPO.276.1", ""},
 		{"EU.EPÜ.108", ""},