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-localization/README.md

@@ -0,0 +1,41 @@
+<p>
+  <a href="https://docs.expo.dev/versions/latest/sdk/localization/">
+    <img
+      src="../../.github/resources/expo-localization.svg"
+      alt="expo-localization"
+      height="64" />
+  </a>
+</p>
+
+Provides an interface for native user localization information.
+
+# API documentation
+
+- [Documentation for the main branch](https://github.com/expo/expo/blob/main/docs/pages/versions/unversioned/sdk/localization.mdx)
+- [Documentation for the latest stable release](https://docs.expo.dev/versions/latest/sdk/localization/)
+
+# Installation in managed Expo projects
+
+For [managed](https://docs.expo.dev/archive/managed-vs-bare/) Expo projects, please follow the installation instructions in the [API documentation for the latest stable release](https://docs.expo.dev/versions/latest/sdk/localization/).
+
+# Installation in bare React Native projects
+
+For bare React Native projects, you must ensure that you have [installed and configured the `expo` package](https://docs.expo.dev/bare/installing-expo-modules/) before continuing.
+
+### Add the package to your npm dependencies
+
+```
+npx expo install expo-localization
+```
+
+### Configure for iOS
+
+Run `npx pod-install` after installing the npm package.
+
+### Configure for Android
+
+No additional set up necessary.
+
+# Contributing
+
+Contributions are very welcome! Please refer to guidelines described in the [contributing guide](https://github.com/expo/expo#contributing).