fix+upstream: hooks-order crash, ConfirmDialog/PageHeader/skeletons, styled error boundary

Hoists hooks above early return (render-time Navigate); ports finance's
ConfirmDialog/PageHeader/loading/states + APC error-copy mapper; removes
window.confirm, dead appbar search, and seeded fake notifications; wires toasts.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app/lib/notifications.ts

@@ -127,29 +127,3 @@ export function useNotifications(): AppNotification[] {
 export function unreadCount(items: AppNotification[]): number {
   return items.filter((n) => !n.readAt).length
 }
-
-/** Seed a few demo notifications on first load so the bell isn't empty. */
-export function seedIfEmpty() {
-  if (typeof window === "undefined") return
-  if (localStorage.getItem(STORAGE_KEY)) return
-  const now = Date.now()
-  const seed: AppNotification[] = [
-    {
-      id: newId(),
-      kind: "info",
-      title: "Welcome",
-      body: "Tag elements with data-action and the assistant can drive them.",
-      href: "/assistant",
-      createdAt: now - 60_000,
-    },
-    {
-      id: newId(),
-      kind: "success",
-      title: "Profile saved",
-      body: "Your display name and avatar are live across the app.",
-      href: "/profile",
-      createdAt: now - 5 * 60_000,
-    },
-  ]
-  writeToStorage(seed)
-}