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/route-tree.gen.ts

@@ -0,0 +1,15 @@
+import { Route as rootRoute } from "./routes/__root"
+import { Route as loginRoute } from "./routes/login"
+import { Route as dashboardRoute } from "./routes/_dashboard"
+import { Route as dashboardIndexRoute } from "./routes/_dashboard/index"
+import { Route as dashboardFeedRoute } from "./routes/_dashboard/feed"
+import { Route as dashboardSourceRoute } from "./routes/_dashboard/sources.$sourceId"
+
+export const routeTree = rootRoute.addChildren([
+  loginRoute,
+  dashboardRoute.addChildren([
+    dashboardIndexRoute,
+    dashboardFeedRoute,
+    dashboardSourceRoute,
+  ]),
+])