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/components/cases/sync-indicator.tsx

@@ -2,17 +2,7 @@
 
 import { useGitStatus } from "@/lib/api/cases";
 import { CheckCircle2, AlertCircle, Clock, CloudOff } from "lucide-react";
-
-function formatRelative(iso: string): string {
-  const diff = Date.now() - new Date(iso).getTime();
-  const mins = Math.floor(diff / 60_000);
-  if (mins < 1) return "עכשיו";
-  if (mins < 60) return `לפני ${mins} דק׳`;
-  const hours = Math.floor(mins / 60);
-  if (hours < 24) return `לפני ${hours} שע׳`;
-  const days = Math.floor(hours / 24);
-  return `לפני ${days} ימים`;
-}
+import { formatRelative } from "@/lib/format-date";
 
 export function SyncIndicator({ caseNumber }: { caseNumber?: string }) {
   const { data, isLoading } = useGitStatus(caseNumber);