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/Settings/React-RCTSettings.podspec

@@ -0,0 +1,56 @@
+# 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.
+
+require "json"
+
+package = JSON.parse(File.read(File.join(__dir__, "..", "..", "package.json")))
+version = package['version']
+
+source = { :git => '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+  # This is an unpublished version, use the latest commit hash of the react-native repo, which we’re presumably in.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
+
+folly_config = get_folly_config()
+folly_compiler_flags = folly_config[:compiler_flags]
+folly_version = folly_config[:version]
+
+header_search_paths = [
+  "\"$(PODS_ROOT)/RCT-Folly\"",
+  "\"${PODS_ROOT}/Headers/Public/React-Codegen/react/renderer/components\"",
+]
+
+Pod::Spec.new do |s|
+  s.name                   = "React-RCTSettings"
+  s.version                = version
+  s.summary                = "A wrapper for NSUserDefaults, a persistent key-value store available only on iOS."
+  s.homepage               = "https://reactnative.dev/"
+  s.documentation_url      = "https://reactnative.dev/docs/settings"
+  s.license                = package["license"]
+  s.author                 = "Meta Platforms, Inc. and its affiliates"
+  s.platforms              = min_supported_versions
+  s.compiler_flags         = folly_compiler_flags + ' -Wno-nullability-completeness'
+  s.source                 = source
+  s.source_files           = "*.{m,mm}"
+  s.preserve_paths         = "package.json", "LICENSE", "LICENSE-docs"
+  s.header_dir             = "RCTSettings"
+  s.pod_target_xcconfig    = {
+                               "USE_HEADERMAP" => "YES",
+                               "CLANG_CXX_LANGUAGE_STANDARD" => "c++20",
+                               "HEADER_SEARCH_PATHS" => header_search_paths.join(' ')
+                             }
+
+  s.dependency "RCT-Folly", folly_version
+  s.dependency "RCTTypeSafety"
+  s.dependency "React-jsi"
+  s.dependency "React-Core/RCTSettingsHeaders"
+
+  add_dependency(s, "React-Codegen", :additional_framework_paths => ["build/generated/ios"])
+  add_dependency(s, "ReactCommon", :subspec => "turbomodule/core", :additional_framework_paths => ["react/nativemodule/core"])
+  add_dependency(s, "React-NativeModulesApple", :additional_framework_paths => ["build/generated/ios"])
+end