android(call): Increment 2a — native LiveKit call audio, background service, speaker/BT routing

Replaces WebView call media on Android with a native LiveKit connection (iOS
parity), so call audio survives backgrounding and the output can be switched
to Speaker/Bluetooth/Earpiece — the #3 (missing speaker control) and #4
(background audio) items.

Gated behind a new, default-off server flag ANDROID_NATIVE_MEDIA (independent
of ANDROID_CALLS, which only governs the native ring). Flag off = today's
WebView media, video included; flag on = native audio (video is Increment 2b,
so enable it for VOICE testing first). No behavior change until flipped.

Native (mobile/plugins/native-call/android):
- build.gradle: add kotlin-android + io.livekit:livekit-android 2.29.2 (+ twilio
  audioswitch, coroutines) + JitPack repo; minSdk 24 (LiveKit floor).
- CallMedia.kt: LiveKit Room wrapper — connect/mic/disconnect + AudioSwitchHandler
  routing (auto + selectDevice) and route-change events.
- CallForegroundService.java: microphone-type foreground service for background
  audio (no-ops without RECORD_AUDIO so it never crashes the call).
- NativeCallPlugin.java: real bodies for reportOutgoingCall/reconnectRoom/setMuted
  /endCall + new setAudioRoute/getAudioRoute; fires callConnected/callError/audioRoute.
- AndroidManifest: FG service + FOREGROUND_SERVICE(_MICROPHONE)/RECORD_AUDIO/
  MODIFY_AUDIO_SETTINGS/BLUETOOTH_CONNECT.
- android-patch.js: bump the generated app minSdk to 24.

Server:
- config.js/routes.js: ANDROID_NATIVE_MEDIA → /api/meetings/config.androidNativeMedia.

Web (home.html):
- Android flips to the native-media path when androidNativeMedia is set; the
  existing outgoing/answer/mic/end code then drives the plugin unchanged.
- Speaker button wired for Android native: cycles speaker/earpiece/bluetooth via
  NC.setAudioRoute and reflects the real output from the audioRoute event.

Video stays no-op on the native path (Increment 2b).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

mobile/plugins/native-call/android/build.gradle

@@ -1,32 +1,48 @@
 // Android build for the native-call plugin. Mirrors the official @capacitor/* plugin module layout (see
-// node_modules/@capacitor/status-bar/android/build.gradle) so it drops into the CI-generated app exactly like
-// the plugins that already build. Java (not Kotlin) to match the proven official-plugin structure — no extra
-// kotlin-gradle-plugin wiring in the library module, one less thing to fail when authored blind.
+// node_modules/@capacitor/status-bar/android/build.gradle) so it drops into the CI-generated app like the
+// plugins that already build.
+//
+// INCREMENT 2 adds native LiveKit call media (background audio + Speaker/Bluetooth routing), which is a Kotlin +
+// coroutines SDK — so this module now also applies kotlin-android (the ring/plugin glue stays Java). Capacitor
+// pulls the Kotlin stdlib via a BOM but does NOT apply the Kotlin Gradle plugin at the root, so we bring it here
+// (the standard community-plugin pattern); the classpath is additive to the generated root's AGP.
 ext {
     junitVersion = project.hasProperty('junitVersion') ? rootProject.ext.junitVersion : '4.13.2'
     androidxCoreVersion = project.hasProperty('androidxCoreVersion') ? rootProject.ext.androidxCoreVersion : '1.12.0'
     androidxAppCompatVersion = project.hasProperty('androidxAppCompatVersion') ? rootProject.ext.androidxAppCompatVersion : '1.6.1'
     // Same FCM version the @capacitor/push-notifications plugin pulls in, so we don't fork the Firebase version.
     firebaseMessagingVersion = project.hasProperty('firebaseMessagingVersion') ? rootProject.ext.firebaseMessagingVersion : '23.3.1'
+    // Follow the project's Kotlin (Capacitor pins kotlin_version at the root); fall back to a recent stable.
+    bzcKotlinVersion = rootProject.hasProperty('kotlin_version') ? rootProject.ext.kotlin_version : '1.9.24'
+    // LiveKit Android SDK — native background call media (Increment 2). Pinned; bump deliberately.
+    livekitVersion = '2.29.2'
+    audioswitchVersion = '1.2.0'
+    coroutinesVersion = '1.8.1'
 }
 
 buildscript {
+    ext.bzc_kotlin = rootProject.hasProperty('kotlin_version') ? rootProject.ext.kotlin_version : '1.9.24'
     repositories {
         google()
         mavenCentral()
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:8.2.1'
+        // Kotlin Gradle plugin so this module can compile the .kt LiveKit wrapper. Additive to the root's AGP.
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$bzc_kotlin"
     }
 }
 
 apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
 
 android {
     namespace "com.bizgaze.connect.nativecall"
-    compileSdk project.hasProperty('compileSdkVersion') ? rootProject.ext.compileSdkVersion : 34
+    // LiveKit 2.29 compiles against a recent platform; honor the CI root (Capacitor 8 = 35) and floor at 35.
+    compileSdk project.hasProperty('compileSdkVersion') ? rootProject.ext.compileSdkVersion : 35
     defaultConfig {
-        minSdkVersion project.hasProperty('minSdkVersion') ? rootProject.ext.minSdkVersion : 23
+        // LiveKit Android's floor. The app min is bumped to 24 in CI (android-patch.js) so the merge holds.
+        minSdkVersion 24
         targetSdkVersion project.hasProperty('targetSdkVersion') ? rootProject.ext.targetSdkVersion : 34
         versionCode 1
         versionName "1.0"
@@ -44,11 +60,16 @@ android {
         sourceCompatibility JavaVersion.VERSION_17
         targetCompatibility JavaVersion.VERSION_17
     }
+    kotlinOptions {
+        jvmTarget = '17'
+    }
 }
 
 repositories {
     google()
     mavenCentral()
+    // LiveKit pulls transitive artifacts (its WebRTC fork) that live on JitPack.
+    maven { url 'https://jitpack.io' }
 }
 
 dependencies {
@@ -62,4 +83,11 @@ dependencies {
     // RemoteMessage / FirebaseMessaging (transitive from the push plugin, but declared so this module compiles
     // against it directly; same version → no resolution conflict).
     implementation "com.google.firebase:firebase-messaging:$firebaseMessagingVersion"
+    // Kotlin + coroutines for the native LiveKit media wrapper (CallMedia.kt).
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:$bzcKotlinVersion"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:$coroutinesVersion"
+    // Native call media (background audio) + audio-device routing (speaker/bluetooth/earpiece).
+    implementation "io.livekit:livekit-android:$livekitVersion"
+    // AudioDevice types used by LiveKit's AudioSwitchHandler; declared so they're on our compile classpath.
+    implementation "com.twilio:audioswitch:$audioswitchVersion"
 }