fix(web-ui): display all human-facing timestamps in Asia/Jerusalem (deterministic)

Storage stays UTC (DB TIMESTAMPTZ, API ISO-UTC) — only the display layer is
localized, and now deterministically: every timestamp renders pinned to
Asia/Jerusalem via a single Intl-based formatter, so SSR (UTC container) and
the browser agree on any runtime. No layout/visible-format change — only the tz.

- New single date formatter web-ui/src/lib/format-date.ts (G2): formatDate /
  formatDateShort / formatDateLong / formatDateTime / formatDateTimeFull /
  formatTime / formatIsoDate + Israel helpers getIsraelYear / israelDayKey /
  israelMidnightMs / israelParts + formatRelative (long/short/tight wording).
- Routed all ad-hoc toLocaleDateString/toLocaleTimeString/toLocaleString +
  hand-rolled new Date(...).get*() / toISOString().slice(0,10) timestamp call
  sites (30 files) through it. Number toLocaleString left untouched.
- Spec: added INV-UI9 to docs/spec/X6 (UTC storage, Asia/Jerusalem display).

Display-only; no layout/design/IA change → Claude Design gate N/A.
Invariants: G2 (single date formatter, no parallel ad-hoc formatting), INV-UI9.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web-ui/src/app/archive/page.tsx

@@ -28,19 +28,7 @@ import {
 import { useCases, useRestoreCase, type Case } from "@/lib/api/cases";
 import { subtypeOf } from "@/components/cases/appeal-type-bars";
 import { APPEAL_SUBTYPE_LABELS, type AppealSubtype } from "@/lib/practice-area";
-
-function formatDate(iso?: string | null) {
-  if (!iso) return "—";
-  try {
-    return new Date(iso).toLocaleDateString("he-IL", {
-      day: "2-digit",
-      month: "2-digit",
-      year: "numeric",
-    });
-  } catch {
-    return iso;
-  }
-}
+import { formatDate, getIsraelYear } from "@/lib/format-date";
 
 // type chip styling per mockup 05 (.t-lic / .t-bet / .t-comp)
 const TYPE_CHIP: Record<string, string> = {
@@ -177,8 +165,8 @@ export default function ArchivePage() {
     const set = new Set<string>();
     for (const c of rows) {
       if (!c.archived_at) continue;
-      const y = new Date(c.archived_at).getFullYear();
-      if (!Number.isNaN(y)) set.add(String(y));
+      const y = getIsraelYear(c.archived_at);
+      if (y !== null) set.add(String(y));
     }
     return [...set].sort((a, b) => Number(b) - Number(a));
   }, [rows]);
@@ -209,7 +197,7 @@ export default function ArchivePage() {
     if (yearFilter !== "all") {
       all = all.filter((r) => {
         const iso = r.original.archived_at;
-        return iso != null && String(new Date(iso).getFullYear()) === yearFilter;
+        return iso != null && String(getIsraelYear(iso)) === yearFilter;
       });
     }
     return all;