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/operations/system-health-section.tsx

@@ -14,6 +14,7 @@ import { Card, CardContent } from "@/components/ui/card";
 import { Badge } from "@/components/ui/badge";
 import { Skeleton } from "@/components/ui/skeleton";
 import { useDiagnostics, type DiagDoc } from "@/lib/api/system";
+import { formatDateShort, formatRelative } from "@/lib/format-date";
 
 const TABLE_LABELS: Record<string, string> = {
   cases: "תיקים",
@@ -25,16 +26,10 @@ const TABLE_LABELS: Record<string, string> = {
 
 function formatRelativeTime(iso: string | null) {
   if (!iso) return "—";
-  const then = new Date(iso);
-  const diffMs = Date.now() - then.getTime();
-  const min = Math.floor(diffMs / 60000);
-  if (min < 1) return "עכשיו";
-  if (min < 60) return `לפני ${min} דקות`;
-  const hr = Math.floor(min / 60);
-  if (hr < 24) return `לפני ${hr} שעות`;
-  const days = Math.floor(hr / 24);
-  if (days < 30) return `לפני ${days} ימים`;
-  return then.toLocaleDateString("he-IL");
+  const min = Math.floor((Date.now() - new Date(iso).getTime()) / 60000);
+  // Past 30 days, fall back to an absolute Israel-time date.
+  if (min >= 30 * 24 * 60) return formatDateShort(iso);
+  return formatRelative(iso, { units: "long" });
 }
 
 function DocRow({ doc, tone }: { doc: DiagDoc; tone: "danger" | "warn" }) {