v2.4.0 — OIDC login, OpenStreetMap search, account management

Features:
- Single Sign-On (OIDC) — login with Google, Apple, Authentik, Keycloak
- OpenStreetMap place search as free fallback when no Google API key
- Change password in user settings
- Delete own account (with last-admin protection)
- Last login column in admin user management
- SSO badge and provider info in user settings
- Google API key "Recommended" badge in admin panel

Improvements:
- API keys load correctly after page reload
- Validate auto-saves keys before testing
- Time format respects 12h/24h setting everywhere
- Dark mode fixes for popups and backup buttons
- Admin stats: removed photos, 4-column layout
- Profile picture upload button on avatar overlay
- TravelStats duplicate key fix
- Backup panel dark mode support

client/src/App.jsx

@@ -55,7 +55,7 @@ function RootRedirect() {
 }
 
 export default function App() {
-  const { loadUser, token, isAuthenticated, demoMode, setDemoMode } = useAuthStore()
+  const { loadUser, token, isAuthenticated, demoMode, setDemoMode, setHasMapsKey } = useAuthStore()
   const { loadSettings } = useSettingsStore()
 
   useEffect(() => {
@@ -64,6 +64,7 @@ export default function App() {
     }
     authApi.getAppConfig().then(config => {
       if (config?.demo_mode) setDemoMode(true)
+      if (config?.has_maps_key !== undefined) setHasMapsKey(config.has_maps_key)
     }).catch(() => {})
   }, [])