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/android/build.gradle

@@ -0,0 +1,99 @@
+apply plugin: 'com.android.library'
+
+// Import autolinking script
+apply from: "../scripts/autolinking.gradle"
+
+def expoModulesCorePlugin = new File(project(":expo-modules-core").projectDir.absolutePath, "ExpoModulesCorePlugin.gradle")
+apply from: expoModulesCorePlugin
+applyKotlinExpoModulesCorePlugin()
+useDefaultAndroidSdkVersions()
+useExpoPublishing()
+
+static def versionToNumber(major, minor, patch) {
+  return patch * 100 + minor * 10000 + major * 1000000
+}
+
+def getRNVersion() {
+  def nodeModulesVersion = providers.exec {
+    workingDir(projectDir)
+    commandLine("node", "-e", "console.log(require('react-native/package.json').version);")
+  }.standardOutput.asText.get().trim()
+
+  def version = safeExtGet("reactNativeVersion", nodeModulesVersion)
+  def coreVersion = version.split("-")[0]
+  def (major, minor, patch) = coreVersion.tokenize('.').collect { it.toInteger() }
+
+  return versionToNumber(
+      major,
+      minor,
+      patch
+  )
+}
+
+ensureDependeciesWereEvaluated(project)
+
+group = 'host.exp.exponent'
+version = '51.0.39'
+
+buildscript {
+  // Simple helper that allows the root project to override versions declared by this library.
+  ext.safeExtGet = { prop, fallback ->
+    rootProject.ext.has(prop) ? rootProject.ext.get(prop) : fallback
+  }
+}
+
+android {
+  namespace "expo.core"
+  defaultConfig {
+    versionCode 1
+    versionName "51.0.39"
+    consumerProguardFiles("proguard-rules.pro")
+  }
+  testOptions {
+    unitTests.includeAndroidResources = true
+  }
+
+  sourceSets {
+    main {
+      java {
+        srcDirs += new File(project.buildDir, generatedFilesSrcDir)
+
+        def rnVersion = getRNVersion()
+        if (rnVersion >= versionToNumber(0, 74, 0)) {
+          srcDirs += "src/reactWrappers"
+        }
+      }
+    }
+  }
+}
+
+dependencies { dependencyHandler ->
+  implementation 'com.facebook.react:react-android'
+
+  testImplementation 'junit:junit:4.13.2'
+  testImplementation 'androidx.test:core:1.5.0'
+  testImplementation "com.google.truth:truth:1.1.2"
+  testImplementation 'io.mockk:mockk:1.13.5'
+
+  // Link expo modules as dependencies of the adapter. It uses `api` configuration so they all will be visible for the app as well.
+  // A collection of the dependencies depends on the options passed to `useExpoModules` in your project's `settings.gradle`.
+  addExpoModulesDependencies(dependencyHandler, project)
+}
+
+// A task generating a package list of expo modules.
+task generateExpoModulesPackageListTask {
+  def modulesConfig = getModulesConfig()
+  def outputPath = getGenerateExpoModulesPackagesListPath()
+  if (modulesConfig) {
+    outputs.file(file(outputPath))
+    inputs.property("modulesConfig", modulesConfig)
+  }
+
+  // TOOD(@lukmccall): fix not working with configuration cache enabled
+  doLast {
+    generateExpoModulesPackageList()
+  }
+}
+
+// Run that task during prebuilding phase.
+preBuild.dependsOn "generateExpoModulesPackageListTask"