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/react-native/Libraries/Renderer/README.md

@@ -0,0 +1,22 @@
+# React & React Native Versions
+
+This page describes how React and React Native versions interact each other.
+The version alignment between the two frameworks relies on two synchronization points:
+
+1. The versions in the `package.json` of the new app template. For example [for React Native 0.68.1](https://github.com/facebook/react-native/blob/0.68-stable/template/package.json#L12-L15) the versions are aligned as follows:
+
+```
+  "dependencies": {
+    "react": "17.0.2",
+    "react-native": "0.68.1"
+  },
+```
+
+1. The React renderers **shipped** with React Native inside this folder, the [./Libraries/Renderer](https://github.com/facebook/react-native/tree/main/Libraries/Renderer) folder, of React Native.
+
+This practically means that you **can't bump** the version of React in your `package.json` to a later version,
+as you will still be using the older renderer from the folder mentioned above. Bumping the react version in your `package.json` will lead to unexpected behaviors.
+
+For the sake of React 18, the first version of React Native compatible with React 18 is **0.69.0**. Users on React Native 0.68.0 and previous versions won't be able to use React 18.
+
+If you use the `react-native upgrade` command or the React Native Upgrade Helper, you'll bump to the correct React version once you upgrade React Native.