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/training/chat-panel.tsx

@@ -41,6 +41,7 @@ import {
   useDeleteChat,
   type ChatMessage,
 } from "@/lib/api/training";
+import { formatDateShort } from "@/lib/format-date";
 import { useQueryClient } from "@tanstack/react-query";
 
 export function ChatPanel() {
@@ -200,7 +201,7 @@ function ConversationsSidebar({
                       <span className="tabular-nums">{c.message_count}</span>
                       <MessageSquare className="w-3 h-3" />
                       <span className="grow text-end">
-                        {new Date(c.last_message_at).toLocaleDateString("he-IL")}
+                        {formatDateShort(c.last_message_at)}
                       </span>
                       <button
                         onClick={(e) => { e.stopPropagation(); onDelete(c.id); }}

web-ui/src/components/training/corpus-panel.tsx

@@ -11,6 +11,7 @@ import { Badge } from "@/components/ui/badge";
 import { Skeleton } from "@/components/ui/skeleton";
 import { useCorpus, useDeleteCorpusEntry, type CorpusDecision } from "@/lib/api/training";
 import { CorpusDetailDrawer } from "./corpus-detail-drawer";
+import { formatDateShort as formatDate } from "@/lib/format-date";
 
 /*
  * Corpus tab: table of all decisions currently in the style corpus.
@@ -30,15 +31,6 @@ function formatChars(n: number) {
   return `${(n / 1000).toFixed(1)}K`;
 }
 
-function formatDate(iso: string) {
-  if (!iso) return "—";
-  try {
-    return new Date(iso).toLocaleDateString("he-IL");
-  } catch {
-    return iso;
-  }
-}
-
 function Row({
   item, onOpen,
 }: { item: CorpusDecision; onOpen: () => void }) {

web-ui/src/components/training/curator-portrait-panel.tsx

@@ -32,6 +32,7 @@ import { Skeleton } from "@/components/ui/skeleton";
 import { ScrollArea } from "@/components/ui/scroll-area";
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
 import { Markdown } from "@/components/ui/markdown";
+import { formatDateShort, formatDateTimeFull } from "@/lib/format-date";
 import {
   useCuratorPrompt,
   useCuratorStats,
@@ -256,7 +257,7 @@ function RecentFindings() {
                 )}
                 <span className="grow text-ink-muted text-end">
                   <Clock className="w-3 h-3 inline me-1" />
-                  {new Date(f.created_at).toLocaleDateString("he-IL")}
+                  {formatDateShort(f.created_at)}
                 </span>
               </div>
               <p className="text-sm text-ink leading-relaxed">{f.lesson_text}</p>
@@ -291,7 +292,7 @@ function CuratorPromptCard() {
             <h3 className="text-navy font-semibold">{data.filename}</h3>
             <p className="text-[0.72rem] text-ink-muted">
               {data.bytes.toLocaleString("he-IL")} בייטים ·
-              עודכן: {new Date(data.last_modified * 1000).toLocaleString("he-IL")}
+              עודכן: {formatDateTimeFull(data.last_modified * 1000)}
             </p>
           </div>
           <Button asChild variant="outline" size="sm">

web-ui/src/components/training/learning-panel.tsx

@@ -9,6 +9,7 @@ import {
   useReconciliationLedger, useStyleDistance, usePairDetail, usePromoteLearning,
   type DraftFinalPair,
 } from "@/lib/api/learning";
+import { formatDateShort as fmtDate } from "@/lib/format-date";
 
 /**
  * /training "למידה" tab (T6/T13) — the reconciliation ledger (INV-LRN4): every
@@ -28,11 +29,6 @@ const STATUS_CLASS: Record<string, string> = {
   lessons_folded: "bg-emerald-50 text-emerald-800 border-emerald-300/60",
 };
 
-function fmtDate(iso: string | null) {
-  if (!iso) return "—";
-  try { return new Date(iso).toLocaleDateString("he-IL"); } catch { return iso; }
-}
-
 function StyleDistanceDetail({ caseNumber }: { caseNumber: string }) {
   const { data, isPending, error } = useStyleDistance(caseNumber);
   if (isPending) return <Loader2 className="w-4 h-4 animate-spin text-ink-muted" />;

web-ui/src/components/training/lessons-tab.tsx

@@ -37,6 +37,7 @@ import {
   usePatchLesson,
   type DecisionLesson,
 } from "@/lib/api/training";
+import { formatDateShort } from "@/lib/format-date";
 
 const CATEGORIES = [
   { value: "general", label: "כללי" },
@@ -224,7 +225,7 @@ function LessonItem({
             {reviewBadge.label}
           </Badge>
           <span className="grow text-ink-muted tabular-nums">
-            {new Date(lesson.created_at).toLocaleDateString("he-IL")}
+            {formatDateShort(lesson.created_at)}
           </span>
         </div>