feat: integrate flutter_local_notifications for enhanced voice call notifications

- Added flutter_local_notifications dependency to manage notifications during voice calls.
- Implemented notification handling in VoiceCallService to update call status and manage user interactions.
- Enabled wake lock functionality to keep the screen on during calls and prevent audio interruptions.
- Updated AndroidManifest.xml to include necessary permissions for Bluetooth and foreground services.
- Enhanced notification actions to allow users to mute, unmute, or end calls directly from notifications.

android/app/build.gradle.kts

@@ -31,6 +31,8 @@ android {
         // Align with modern Android Gradle Plugin requirements
         sourceCompatibility = JavaVersion.VERSION_17
         targetCompatibility = JavaVersion.VERSION_17
+        // Enable core library desugaring for flutter_local_notifications
+        isCoreLibraryDesugaringEnabled = true
     }
 
     kotlinOptions {
@@ -73,6 +75,9 @@ dependencies {
     implementation("androidx.activity:activity:1.9.2")
     implementation("androidx.core:core:1.13.1")
     implementation("androidx.activity:activity-ktx:1.9.2")
+
+    // Core library desugaring for flutter_local_notifications
+    coreLibraryDesugaring("com.android.tools:desugar_jdk_libs:2.1.4")
 }
 
 flutter {