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/i18next/README.md

@@ -0,0 +1,61 @@
+# i18next: learn once - translate everywhere [![Tweet](https://img.shields.io/twitter/url/http/shields.io.svg?style=social)](https://twitter.com/intent/tweet?text=Awesome%20i18next:%20learn%20once%20-%20translate%20everywhere%20-%20the%20internationalization%20ecosystem%20&url=https://github.com/i18next/i18next&via=jamuhl&hashtags=i18n,javascript,dev)
+
+[![CI](https://github.com/i18next/i18next/actions/workflows/CI.yml/badge.svg)](https://github.com/i18next/i18next/actions/workflows/CI.yml)
+[![Code Climate](https://codeclimate.com/github/codeclimate/codeclimate/badges/gpa.svg)](https://codeclimate.com/github/i18next/i18next)
+[![Coveralls](https://img.shields.io/coveralls/i18next/i18next/master.svg?style=flat-square)](https://coveralls.io/github/i18next/i18next)
+[![Package Quality](https://packagequality.com/shield/i18next.svg)](https://packagequality.com/#?package=i18next)
+[![cdnjs version](https://img.shields.io/cdnjs/v/i18next.svg?style=flat-square)](https://cdnjs.com/libraries/i18next)
+[![npm version](https://img.shields.io/npm/v/i18next.svg?style=flat-square)](https://www.npmjs.com/package/i18next)
+![npm](https://img.shields.io/npm/dw/i18next)
+[![Gurubase](https://img.shields.io/badge/Gurubase-Ask%20i18next%20Guru-006BFF)](https://gurubase.io/g/i18next)
+
+i18next is a very popular internationalization framework for browser or any other javascript environment (eg. Node.js, Deno).
+
+![ecosystem](https://raw.githubusercontent.com/i18next/i18next/master/assets/i18next-ecosystem.jpg)
+
+i18next provides:
+
+- Flexible connection to [backend](https://www.i18next.com/overview/plugins-and-utils#backends) (loading translations via xhr, ...)
+- Optional [caching](https://www.i18next.com/how-to/caching), user [language detection](https://www.i18next.com/overview/plugins-and-utils#language-detector), ...
+- Proper [pluralizations](https://www.i18next.com/translation-function/plurals)
+- Translation [context](https://www.i18next.com/translation-function/context)
+- [Nesting](https://www.i18next.com/translation-function/nesting), [Variable replacement](https://www.i18next.com/translation-function/interpolation)
+- Flexibility: [Use it everywhere](https://www.i18next.com/overview/supported-frameworks)
+- Extensibility: eg. [sprintf](https://www.i18next.com/overview/plugins-and-utils#post-processors)
+- ...
+
+For more information visit the website:
+
+- [Getting started](https://www.i18next.com/overview/getting-started)
+- [Translation Functionality](https://www.i18next.com/translation-function/essentials)
+- [API](https://www.i18next.com/overview/api)
+
+Our focus is providing the core to building a booming ecosystem. Independent of the building blocks you choose, be it react, angular or even good old jquery proper translation capabilities are just [one step away](https://www.i18next.com/overview/supported-frameworks).
+
+### Documentation
+
+The general i18next documentation is published on [www.i18next.com](https://www.i18next.com) and PR changes can be supplied [here](https://github.com/i18next/i18next-gitbook).
+
+The react specific documentation is published on [react.i18next.com](https://react.i18next.com) and PR changes can be supplied [here](https://github.com/i18next/react-i18next-gitbook).
+
+---
+
+<h3 align="center">Gold Sponsors</h3>
+
+<p align="center">
+  <a href="https://locize.com/" target="_blank">
+    <img src="https://raw.githubusercontent.com/i18next/i18next/master/assets/locize_sponsor_240.gif" width="240px">
+  </a>
+</p>
+
+---
+
+**From the creators of i18next: localization as a service - locize.com**
+
+A translation management system built around the i18next ecosystem - [locize.com](https://locize.com).
+
+![locize](https://locize.com/img/ads/github_locize.png)
+
+With using [locize](https://locize.com/?utm_source=i18next_readme&utm_medium=github) you directly support the future of i18next.
+
+---