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-constants/android/build.gradle

@@ -0,0 +1,26 @@
+apply plugin: 'com.android.library'
+
+group = 'host.exp.exponent'
+version = '16.0.2'
+
+apply from: "../scripts/get-app-config-android.gradle"
+
+def expoModulesCorePlugin = new File(project(":expo-modules-core").projectDir.absolutePath, "ExpoModulesCorePlugin.gradle")
+apply from: expoModulesCorePlugin
+applyKotlinExpoModulesCorePlugin()
+useCoreDependencies()
+useDefaultAndroidSdkVersions()
+useExpoPublishing()
+
+android {
+  namespace "expo.modules.constants"
+  defaultConfig {
+    versionCode 33
+    versionName "16.0.2"
+  }
+}
+
+dependencies {
+  api "androidx.annotation:annotation:1.0.0"
+  implementation "commons-io:commons-io:2.6"
+}

smart-app-city/frontend/node_modules/expo-constants/android/src/main/AndroidManifest.xml

@@ -0,0 +1,3 @@
+<manifest>
+
+</manifest>

smart-app-city/frontend/node_modules/expo-constants/android/src/main/java/expo/modules/constants/ConstantsModule.kt

@@ -0,0 +1,20 @@
+// Copyright 2015-present 650 Industries. All rights reserved.
+package expo.modules.constants
+
+import expo.modules.kotlin.modules.Module
+import expo.modules.kotlin.modules.ModuleDefinition
+
+class ConstantsModule : Module() {
+
+  override fun definition() = ModuleDefinition {
+    Name("ExponentConstants")
+
+    Constants {
+      return@Constants appContext.constants?.constants ?: emptyMap()
+    }
+
+    AsyncFunction<String?>("getWebViewUserAgentAsync") {
+      return@AsyncFunction System.getProperty("http.agent")
+    }
+  }
+}

smart-app-city/frontend/node_modules/expo-constants/android/src/main/java/expo/modules/constants/ConstantsPackage.kt

@@ -0,0 +1,11 @@
+package expo.modules.constants
+
+import android.content.Context
+
+import expo.modules.core.BasePackage
+import expo.modules.core.interfaces.InternalModule
+
+class ConstantsPackage : BasePackage() {
+  override fun createInternalModules(context: Context): List<InternalModule> =
+    listOf(ConstantsService(context))
+}

smart-app-city/frontend/node_modules/expo-constants/android/src/main/java/expo/modules/constants/ConstantsService.kt

@@ -0,0 +1,96 @@
+package expo.modules.constants
+
+import org.apache.commons.io.IOUtils
+
+import expo.modules.core.interfaces.InternalModule
+import expo.modules.interfaces.constants.ConstantsInterface
+
+import android.os.Build
+import android.util.Log
+import android.content.Context
+
+import java.io.FileNotFoundException
+import java.lang.Exception
+import java.nio.charset.StandardCharsets
+import java.util.*
+
+private val TAG = ConstantsService::class.java.simpleName
+private const val CONFIG_FILE_NAME = "app.config"
+
+open class ConstantsService(private val context: Context) : InternalModule, ConstantsInterface {
+  var statusBarHeightInternal = context.resources.getIdentifier("status_bar_height", "dimen", "android")
+    .takeIf { it > 0 }
+    ?.let { (context.resources::getDimensionPixelSize)(it) }
+    ?.let { pixels -> convertPixelsToDp(pixels.toFloat(), context) }
+    ?: 0
+
+  private val sessionId = UUID.randomUUID().toString()
+
+  enum class ExecutionEnvironment(val string: String) {
+    BARE("bare"),
+    STANDALONE("standalone"),
+    STORE_CLIENT("storeClient")
+  }
+
+  override fun getExportedInterfaces(): List<Class<*>> = listOf(ConstantsInterface::class.java)
+
+  override fun getConstants(): Map<String, Any?> {
+    return mutableMapOf(
+      "sessionId" to sessionId,
+      "executionEnvironment" to ExecutionEnvironment.BARE.string,
+      "statusBarHeight" to statusBarHeightInternal,
+      "deviceName" to deviceName,
+      "systemFonts" to systemFonts,
+      "systemVersion" to systemVersion,
+      "manifest" to appConfig,
+      "platform" to mapOf<String, Map<String, Any>>("android" to emptyMap())
+    )
+  }
+
+  // Just use package name in vanilla React Native apps.
+  override fun getAppScopeKey(): String? = context.packageName
+
+  override fun getDeviceName(): String = Build.MODEL
+
+  override fun getStatusBarHeight() = statusBarHeightInternal
+
+  override fun getSystemVersion(): String = Build.VERSION.RELEASE
+
+  // From https://github.com/dabit3/react-native-fonts
+  override fun getSystemFonts() = listOf(
+    "normal",
+    "notoserif",
+    "sans-serif",
+    "sans-serif-light",
+    "sans-serif-thin",
+    "sans-serif-condensed",
+    "sans-serif-medium",
+    "serif",
+    "Roboto",
+    "monospace"
+  )
+
+  private val appConfig: String?
+    get() {
+      try {
+        context.assets.open(CONFIG_FILE_NAME).use {
+            stream ->
+          return IOUtils.toString(stream, StandardCharsets.UTF_8)
+        }
+      } catch (e: FileNotFoundException) {
+        // do nothing, expected in managed apps
+      } catch (e: Exception) {
+        Log.e(TAG, "Error reading embedded app config", e)
+      }
+      return null
+    }
+
+  companion object {
+    private fun convertPixelsToDp(px: Float, context: Context): Int {
+      val resources = context.resources
+      val metrics = resources.displayMetrics
+      val dp = px / (metrics.densityDpi / 160f)
+      return dp.toInt()
+    }
+  }
+}