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/routes/__root.tsx

@@ -0,0 +1,13 @@
+import { createRootRouteWithContext, Outlet } from "@tanstack/react-router"
+import type { QueryClient } from "@tanstack/react-query"
+import { TooltipProvider } from "@/components/ui/tooltip"
+
+export const Route = createRootRouteWithContext<{ queryClient: QueryClient }>()({
+  component: function RootLayout() {
+    return (
+      <TooltipProvider>
+        <Outlet />
+      </TooltipProvider>
+    )
+  },
+})