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-asset/android/build.gradle

@@ -0,0 +1,19 @@
+apply plugin: 'com.android.library'
+
+group = 'expo.modules.asset'
+version = '10.0.10'
+
+def expoModulesCorePlugin = new File(project(":expo-modules-core").projectDir.absolutePath, "ExpoModulesCorePlugin.gradle")
+apply from: expoModulesCorePlugin
+applyKotlinExpoModulesCorePlugin()
+useCoreDependencies()
+useDefaultAndroidSdkVersions()
+useExpoPublishing()
+
+android {
+  namespace "expo.modules.asset"
+  defaultConfig {
+    versionCode 1
+    versionName "10.0.10"
+  }
+}

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

@@ -0,0 +1,2 @@
+<manifest>
+</manifest>

smart-app-city/frontend/node_modules/expo-asset/android/src/main/java/expo/modules/asset/AssetModule.kt

@@ -0,0 +1,98 @@
+package expo.modules.asset
+
+import android.content.Context
+import android.net.Uri
+import expo.modules.interfaces.filesystem.Permission
+import expo.modules.kotlin.AppContext
+import expo.modules.kotlin.exception.CodedException
+import expo.modules.kotlin.exception.Exceptions
+import expo.modules.kotlin.functions.Coroutine
+import expo.modules.kotlin.modules.Module
+import expo.modules.kotlin.modules.ModuleDefinition
+import kotlinx.coroutines.withContext
+import java.io.File
+import java.io.FileInputStream
+import java.net.URI
+import java.security.DigestInputStream
+import java.security.MessageDigest
+
+internal class UnableToDownloadAssetException(url: String) :
+  CodedException("Unable to download asset from url: $url")
+
+class AssetModule : Module() {
+  private val context: Context
+    get() = appContext.reactContext ?: throw Exceptions.AppContextLost()
+
+  private fun getMD5HashOfFilePath(uri: URI): String {
+    val md = MessageDigest.getInstance("MD5")
+    return md.digest(uri.toString().toByteArray()).joinToString("") { "%02x".format(it) }
+  }
+
+  private fun getMD5HashOfFileContent(file: File): String? {
+    return try {
+      FileInputStream(file).use { inputStream ->
+        DigestInputStream(
+          inputStream,
+          MessageDigest.getInstance("MD5")
+        ).use { digestInputStream ->
+          digestInputStream.messageDigest.digest().joinToString(separator = "") { "%02x".format(it) }
+        }
+      }
+    } catch (e: Exception) {
+      e.printStackTrace()
+      null
+    }
+  }
+
+  private suspend fun downloadAsset(appContext: AppContext, uri: URI, localUrl: File): Uri {
+    if (localUrl.parentFile?.exists() != true) {
+      localUrl.mkdirs()
+    }
+
+    if (appContext.filePermission?.getPathPermissions(appContext.reactContext, localUrl.parent)?.contains(Permission.WRITE) != true) {
+      throw UnableToDownloadAssetException(uri.toString())
+    }
+
+    return withContext(appContext.backgroundCoroutineScope.coroutineContext) {
+      try {
+        val inputStream = when {
+          uri.toString().contains(":").not() -> openAssetResourceStream(context, uri.toString())
+          else -> uri.toURL().openStream()
+        }
+        inputStream.use { input ->
+          localUrl.outputStream().use { output ->
+            input.copyTo(output)
+          }
+        }
+        Uri.fromFile(localUrl)
+      } catch (e: Exception) {
+        throw UnableToDownloadAssetException(uri.toString())
+      }
+    }
+  }
+
+  override fun definition() = ModuleDefinition {
+    Name("ExpoAsset")
+
+    AsyncFunction("downloadAsync") Coroutine { uri: URI, md5Hash: String?, type: String ->
+      if (uri.scheme === "file") {
+        return@Coroutine uri
+      }
+
+      val cacheFileId = md5Hash ?: getMD5HashOfFilePath(uri)
+      val cacheDirectory = appContext.cacheDirectory
+
+      val localUrl = File("$cacheDirectory/ExponentAsset-$cacheFileId.$type")
+
+      if (!localUrl.exists()) {
+        return@Coroutine downloadAsset(appContext, uri, localUrl)
+      }
+
+      if (md5Hash == null || md5Hash == getMD5HashOfFileContent(localUrl)) {
+        return@Coroutine Uri.fromFile(localUrl)
+      }
+
+      return@Coroutine downloadAsset(appContext, uri, localUrl)
+    }
+  }
+}

smart-app-city/frontend/node_modules/expo-asset/android/src/main/java/expo/modules/asset/ResourceAsset.kt

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+package expo.modules.asset
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.content.res.Resources
+import java.io.InputStream
+
+/**
+ * Opens an Android resource as stream.
+ */
+internal fun openAssetResourceStream(context: Context, assetName: String): InputStream {
+  val resources = context.resources
+  val resId = findResourceId(context, assetName) ?: throw Resources.NotFoundException(assetName)
+  return resources.openRawResource(resId)
+}
+
+@SuppressLint("DiscouragedApi")
+private fun findResourceId(context: Context, assetName: String): Int? {
+  val resources = context.resources
+  val packageName = context.packageName
+  // react-native core and expo-assets plugin will put resource in `res/raw` or `res/drawable`
+  return resources.getIdentifier(assetName, "raw", packageName).takeIf { it != 0 }
+    ?: resources.getIdentifier(assetName, "drawable", packageName).takeIf { it != 0 }
+}