fix(web): stop flooding console with 401 ApiError during initial load

Five compounding problems caused hundreds of "Console ApiError:
Unauthorized" entries on every load of /dashboard (and friends) while
unauthenticated or while the auth cookie was stale:

1. QueryClient had `throwOnError: true` as a blanket default, so every
   401 from any react-query hook propagated to the nearest error
   boundary instead of staying in the query's `error` state. That
   also invited React to re-render and re-fire the boundary multiple
   times per failing query.

2. React Query retried all failures 3 times with exponential backoff,
   so a single 401 became four requests. 401 isn't fixable by retry,
   so this is just noise.

3. Dashboard layout rendered `<NotificationBell />` unconditionally,
   which polled /notifications/unread-count on mount even when no user
   was signed in → 401 on every mount.

4. Dashboard + Admin layouts had no redirect-to-login guard, so
   protected queries (market-report, heatmap, admin/dashboard, …) all
   mounted and fired against the API before the user ever saw the
   login screen.

5. Admin layout waited on `user` but had no way to distinguish "store
   still initialising" from "user genuinely absent" — so an expired
   cookie left the page stuck on a spinner while the same 401 storm
   played out in the background.

Fixes
- query-client.ts: `throwOnError` and `retry` are now predicates. Only
  5xx / network errors bubble to boundaries and are retried; 4xx
  (auth, validation, not-found) stay in query error state so the
  component can render an empty/auth placeholder.
- auth-store.ts: new `isInitialized` flag set in a finally block at
  the end of `initialize()`. Downstream guards use it to distinguish
  "still booting" from "definitely logged out".
- (dashboard)/layout.tsx: redirects to /login?next=<path> once
  initialised and unauthenticated, and renders a lightweight loading
  screen in the meantime so child queries never mount.
- (admin)/layout.tsx: same guard. Non-ADMIN logged-in users still
  bounce to /dashboard.
- notification-bell.tsx: short-circuits `fetchUnreadCount` when
  `isAuthenticated` is false.

Verified in dev: visiting /vi/dashboard unauthenticated now redirects
to /login?redirect=/dashboard with zero console errors and no
/analytics/… calls to the backend.

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

apps/web/components/notifications/notification-bell.tsx

@@ -4,6 +4,7 @@ import { Bell } from 'lucide-react';
 import { useRouter } from 'next/navigation';
 import { useEffect, useRef } from 'react';
 import { Button } from '@/components/ui/button';
+import { useAuthStore } from '@/lib/auth-store';
 import type { NotificationDto } from '@/lib/notifications-api';
 import { useNotificationsStore } from '@/lib/notifications-store';
 import { cn } from '@/lib/utils';
@@ -19,13 +20,16 @@ export function NotificationBell() {
     markAllAsRead,
     fetchUnreadCount,
   } = useNotificationsStore();
+  const isAuthenticated = useAuthStore((s) => s.isAuthenticated);
   const router = useRouter();
   const dropdownRef = useRef<HTMLDivElement>(null);
 
-  // Fetch unread count on mount
+  // Fetch unread count only when the user is actually signed in — otherwise
+  // the request returns 401 and floods the dev console with ApiError.
   useEffect(() => {
+    if (!isAuthenticated) return;
     fetchUnreadCount();
-  }, [fetchUnreadCount]);
+  }, [fetchUnreadCount, isAuthenticated]);
 
   // Close on click outside
   useEffect(() => {