feat(smart-app): implement complete mobile app MVP

- App.tsx: full navigation (Auth stack + Main tabs with 5 screens)
- Auth: LoginScreen, RegisterScreen, ForgotPasswordScreen
- HomeScreen: dashboard with IoT metrics, weather widget, alerts, quick actions, sensors
- MapScreen: interactive map with layer toggles (6 layers)
- MarketplaceScreen: categories (6), products (5), search
- ChatScreen: AI chat with quick prompts (4), bot responses
- ProfileScreen: user info, stats, menu (9 items), logout
- AlertsScreen: alert list with severity, acknowledge
- SensorsScreen: sensor list with type filters (6 types), search
- ZonesScreen: zone cards with stats
- SettingsScreen: language picker (FR/EN/ES/DE), privacy, about
- Stores: iotStore (sensors, zones, alerts), notificationStore, uiStore + i18n
- Hooks: useSensors, useAlerts, useNotifications, useLocation
- Components: Card, Button, LoadingSpinner, ErrorBoundary, Header
- Services: iotService, notificationService (with axios API client)
- Utils: formatters (temp, AQI, noise, dates), validators (email, password, IBAN)
- Theme: colors.ts with full design system (Blue Ocean palette)
- Ditto: fixed MongoDB connection, new JWT secrets, official gateway image

smart-app-city/frontend/node_modules/expo-camera/ios/SimulatorUtils.swift

@@ -0,0 +1,49 @@
+import ExpoModulesCore
+
+protocol CameraEvent {
+  var onPictureSaved: EventDispatcher { get }
+}
+
+func takePictureForSimulator(
+  _ appContext: AppContext?,
+  _ event: CameraEvent,
+  _ options: TakePictureOptions,
+  _ promise: Promise
+) throws {
+  if options.fastMode {
+    promise.resolve()
+  }
+  let result = try generatePictureForSimulator(appContext: appContext, options: options)
+
+  if options.fastMode {
+    event.onPictureSaved([
+      "data": result,
+      "id": options.id
+    ])
+  } else {
+    promise.resolve(result)
+  }
+}
+
+func generatePictureForSimulator(
+  appContext: AppContext?,
+  options: TakePictureOptions
+) throws -> [String: Any?] {
+  let path = FileSystemUtilities.generatePathInCache(
+    appContext,
+    in: "Camera",
+    extension: ".jpg"
+  )
+
+  let generatedPhoto = ExpoCameraUtils.generatePhoto(of: CGSize(width: 200, height: 200))
+  guard let photoData = generatedPhoto.jpegData(compressionQuality: options.quality) else {
+    throw CameraInvalidPhotoData()
+  }
+
+  return [
+    "uri": ExpoCameraUtils.write(data: photoData, to: path),
+    "width": generatedPhoto.size.width,
+    "height": generatedPhoto.size.height,
+    "base64": options.base64 ? photoData.base64EncodedString() : nil
+  ]
+}