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/scripts/page.tsx

@@ -26,6 +26,7 @@ import {
   useRunScript,
   type ScriptRunResult,
 } from "@/lib/api/scripts";
+import { formatDateLong } from "@/lib/format-date";
 
 /*
  * /scripts — catalog of everything under scripts/, rendered as the
@@ -354,11 +355,7 @@ export default function ScriptsPage() {
 
   const lastModified =
     data?.last_modified != null
-      ? new Date(data.last_modified * 1000).toLocaleDateString("he-IL", {
-          year: "numeric",
-          month: "long",
-          day: "numeric",
-        })
+      ? formatDateLong(data.last_modified * 1000)
       : null;
 
   const giteaBase = data?.gitea_url ?? null;