fix(admin-web): auto-reload on stale dynamic-import chunks after deploy

Listen for vite:preloadError and router onError, force a one-shot reload
(10s cooldown via sessionStorage) when a hashed lazy-loaded module 404s
because a new deploy replaced it. Eliminates the user-visible "Failed to
fetch dynamically imported module" error on login and route navigation.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/admin-web/src/lib/chunk-reload.ts

@@ -0,0 +1,54 @@
+const RELOAD_FLAG_KEY = '__chunk_reload_at'
+const RELOAD_COOLDOWN_MS = 10_000
+
+function shouldReload(): boolean {
+  try {
+    const raw = sessionStorage.getItem(RELOAD_FLAG_KEY)
+    if (!raw) return true
+    const at = Number(raw)
+    if (!Number.isFinite(at)) return true
+    return Date.now() - at > RELOAD_COOLDOWN_MS
+  } catch {
+    return true
+  }
+}
+
+function markReload(): void {
+  try {
+    sessionStorage.setItem(RELOAD_FLAG_KEY, String(Date.now()))
+  } catch {
+    // ignore storage failures (private mode, quota)
+  }
+}
+
+export function reloadForStaleChunk(): boolean {
+  if (!shouldReload()) return false
+  markReload()
+  location.reload()
+  return true
+}
+
+const CHUNK_ERROR_PATTERNS = [
+  /Failed to fetch dynamically imported module/i,
+  /error loading dynamically imported module/i,
+  /Importing a module script failed/i,
+  /Unable to preload CSS/i,
+]
+
+export function isChunkLoadError(err: unknown): boolean {
+  const msg =
+    err instanceof Error
+      ? err.message
+      : typeof err === 'string'
+        ? err
+        : ''
+  return CHUNK_ERROR_PATTERNS.some((re) => re.test(msg))
+}
+
+export function registerChunkReloadHandlers(): void {
+  window.addEventListener('vite:preloadError', (event) => {
+    if (reloadForStaleChunk()) {
+      event.preventDefault()
+    }
+  })
+}