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/README.md

@@ -0,0 +1,10 @@
+# expo
+
+The `expo` package is a single package you can install in any React Native app to begin using Expo modules.
+
+- includes core infrastructure for Expo modules: `expo-modules-core` and `expo-modules-autolinking`.
+- bundles a minimal set of Expo modules that are required by nearly every app, such as `expo-asset`.
+- provides [`@expo/cli`](https://github.com/expo/expo/blob/main/packages/%40expo/cli/README.md), a small CLI that provides a clean interface around both bundlers (such as Metro and Webpack) and native build tools (Xcode, Simulator.app, Android Studio, ADB, etc.), can generate native projects with `npx expo prebuild`, and aligns compatible package versions with `npx expo install`.
+- exposes a JavaScript module that configures an app at runtime as needed to use `expo-font` and to function in Expo Go (optional, only if applicable).
+
+See [CONTRIBUTING](./CONTRIBUTING.md) for instructions on working on this package.