feat: add admin dashboard app (#91)

* feat: add admin dashboard app

- React + Vite + TanStack Router + TanStack Query
- Auth with better-auth (login, session, admin guard)
- Source config management (WeatherKit credentials, user config)
- Feed query panel
- Location push card
- General settings with health check
- CORS middleware for cross-origin auth
- Disable CSRF check in dev mode
- Sonner toasts for mutation feedback

Co-authored-by: Ona <no-reply@ona.com>

* fix: use useQuery instead of getQueryData

Co-authored-by: Ona <no-reply@ona.com>

* refactor: remove backend changes from dashboard PR

Backend CORS/CSRF changes moved to #92.
Source registry removed (sources hardcoded in frontend).

Co-authored-by: Ona <no-reply@ona.com>

---------

Co-authored-by: Ona <no-reply@ona.com>

apps/admin-dashboard/src/App.tsx

@@ -0,0 +1,25 @@
+import { createRouter, RouterProvider } from "@tanstack/react-router"
+import { useQueryClient, type QueryClient } from "@tanstack/react-query"
+
+import { routeTree } from "./route-tree.gen"
+
+const router = createRouter({
+  routeTree,
+  defaultPreload: "intent",
+  context: {
+    queryClient: undefined! as QueryClient,
+  },
+})
+
+declare module "@tanstack/react-router" {
+  interface Register {
+    router: typeof router
+  }
+}
+
+export function App() {
+  const queryClient = useQueryClient()
+  return <RouterProvider router={router} context={{ queryClient }} />
+}
+
+export default App