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/scripts/node-binary.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+# Copyright © 2023 650 Industries.
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+[ -z "$NODE_BINARY" ] && export NODE_BINARY="node"
+
+nodejs_not_found()
+{
+  echo "error: Can't find the '$NODE_BINARY' binary to build the React Native bundle. " \
+       "If you have a non-standard Node.js installation, select your project in Xcode, find " \
+       "'Build Phases' - 'Bundle React Native code and images' and change NODE_BINARY to an " \
+       "absolute path to your node executable. You can find it by invoking 'which node' in the terminal." >&2
+  exit 2
+}
+
+type "$NODE_BINARY" >/dev/null 2>&1 || nodejs_not_found