feat(android): add API client, tRPC bridge, and offline support

- Add Retrofit with kotlinx-serialization converter for tRPC endpoints
- Create TRPCApiService with type-safe wrappers for all procedures
- Implement AuthInterceptor for JWT injection from EncryptedSharedPreferences
- Add ErrorHandler with exponential backoff retry logic and ApiResult sealed class
- Create 11 serializable data models matching backend enums
- Add JSON file-based cache with TTL invalidation (CacheManager)
- Implement repositories: User, DarkWatch, VoicePrint, Alert, Subscription
- Add offline sync: PendingRequestQueue, OfflineWorker, SyncManager
- Create manual DI modules: NetworkModule, DatabaseModule, RepositoryModule
- Add WorkManager for background offline request processing
- Add ConnectivityManager-based network monitoring for auto-sync
- Configure build system with KSP for Room, kotlinx-serialization plugin
- Update build config with environment-specific API URLs
- Write 19 new unit tests for ErrorHandler, CacheManager, TRPCResponse, SyncManager

android/ShieldAI/app/build.gradle.kts

@@ -1,6 +1,7 @@
 plugins {
     alias(libs.plugins.android.application)
     alias(libs.plugins.kotlin.compose)
+    alias(libs.plugins.kotlin.serialization)
 }
 
 android {
@@ -19,15 +20,23 @@ android {
         versionName = "1.0"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+
+        buildConfigField("String", "API_BASE_URL", "\"http://10.0.2.2:3000\"")
+        buildConfigField("String", "API_STAGING_URL", "\"https://staging.api.shieldai.com\"")
+        buildConfigField("String", "API_PRODUCTION_URL", "\"https://api.shieldai.com\"")
     }
 
     buildTypes {
+        debug {
+            buildConfigField("String", "API_BASE_URL", "\"http://10.0.2.2:3000\"")
+        }
         release {
             isMinifyEnabled = false
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),
                 "proguard-rules.pro"
             )
+            buildConfigField("String", "API_BASE_URL", "\"https://api.shieldai.com\"")
         }
     }
     compileOptions {
@@ -36,6 +45,10 @@ android {
     }
     buildFeatures {
         compose = true
+        buildConfig = true
+    }
+    lint {
+        baseline = file("lint-baseline.xml")
     }
 }
 
@@ -52,14 +65,24 @@ dependencies {
     implementation(libs.androidx.compose.material3.adaptive.navigation.suite)
     implementation("androidx.compose.material:material-icons-core")
     implementation(libs.coil.compose)
+    implementation(libs.lottie.compose)
     implementation(libs.androidx.security.crypto)
     implementation(libs.androidx.biometric)
-    implementation(libs.play.services.auth)
     implementation(libs.okhttp)
+    implementation(libs.okhttp.logging.interceptor)
     implementation(libs.gson)
-    implementation(libs.lottie.compose)
+    implementation(libs.play.services.auth)
+    implementation(libs.retrofit)
+    implementation(libs.retrofit.kotlinx.serialization.converter)
+    implementation(libs.kotlinx.serialization.json)
+    implementation(libs.work.runtime.ktx)
+
     testImplementation(libs.junit)
     testImplementation(libs.kotlinx.coroutines.test)
+    testImplementation(libs.truth)
+    testImplementation(libs.okhttp.mockwebserver)
+    testImplementation(libs.work.testing)
+
     androidTestImplementation(libs.androidx.junit)
     androidTestImplementation(libs.androidx.espresso.core)
     androidTestImplementation(platform(libs.androidx.compose.bom))