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/ReactCommon/yoga/Yoga.podspec

@@ -0,0 +1,67 @@
+# 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.
+
+package = JSON.parse(File.read(File.expand_path('../../package.json', __dir__)))
+version = package['version']
+
+source = { :git => ENV['INSTALL_YOGA_FROM_LOCATION'] || 'https://github.com/facebook/react-native.git' }
+if version == '1000.0.0'
+  # This is an unpublished version, use the latest commit hash of the react-native repo, which we’re presumably in.
+  source[:commit] = `git rev-parse HEAD`.strip if system("git rev-parse --git-dir > /dev/null 2>&1")
+else
+  source[:tag] = "v#{version}"
+end
+
+Pod::Spec.new do |spec|
+  spec.name = 'Yoga'
+  spec.version = '0.0.0'
+  spec.license =  { :type => 'MIT' }
+  spec.homepage = 'https://yogalayout.dev'
+  spec.documentation_url = 'https://yogalayout.dev/docs/'
+
+  spec.summary = 'Yoga is a cross-platform layout engine which implements Flexbox.'
+  spec.description = 'Yoga is a cross-platform layout engine enabling maximum collaboration within your team by implementing an API many designers are familiar with, and opening it up to developers across different platforms.'
+
+  spec.authors = 'Facebook'
+  spec.source = source
+
+  spec.module_name = 'yoga'
+  spec.header_dir = 'yoga'
+  spec.requires_arc = false
+  spec.pod_target_xcconfig = {
+      'DEFINES_MODULE' => 'YES'
+  }.merge!(ENV['USE_FRAMEWORKS'] != nil ? {
+    'HEADER_SEARCH_PATHS' => '"$(PODS_TARGET_SRCROOT)"'
+} : {})
+
+  spec.compiler_flags = [
+      '-fno-omit-frame-pointer',
+      '-fexceptions',
+      '-Wall',
+      '-Werror',
+      '-std=c++20',
+      '-fPIC'
+  ]
+
+  # Pinning to the same version as React.podspec.
+  spec.platforms = min_supported_versions
+
+  # Set this environment variable when *not* using the `:path` option to install the pod.
+  # E.g. when publishing this spec to a spec repo.
+  source_files = 'yoga/**/*.{cpp,h}'
+  source_files = File.join('ReactCommon/yoga', source_files) if ENV['INSTALL_YOGA_WITHOUT_PATH_OPTION']
+  spec.source_files = source_files
+  spec.header_mappings_dir = 'yoga'
+
+  public_header_files = 'yoga/*.h'
+  public_header_files = File.join('ReactCommon/yoga', public_header_files) if ENV['INSTALL_YOGA_WITHOUT_PATH_OPTION']
+  spec.public_header_files = public_header_files
+
+  # Fabric must be able to access private headers (which should not be included in the umbrella header)
+  all_header_files = 'yoga/**/*.h'
+  all_header_files = File.join('ReactCommon/yoga', all_header_files) if ENV['INSTALL_YOGA_WITHOUT_PATH_OPTION']
+  spec.private_header_files = Dir.glob(all_header_files) - Dir.glob(public_header_files)
+  spec.preserve_paths = [all_header_files]
+end