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>

apps/admin-dashboard/.prettierrc

@@ -0,0 +1,11 @@
+{
+  "endOfLine": "lf",
+  "semi": false,
+  "singleQuote": false,
+  "tabWidth": 2,
+  "trailingComma": "es5",
+  "printWidth": 80,
+  "plugins": ["prettier-plugin-tailwindcss"],
+  "tailwindStylesheet": "src/index.css",
+  "tailwindFunctions": ["cn", "cva"]
+}