Fix iOS build: use LiveKit 2.15.3 audio API (drop nonexistent setEngineAvailability)

The build failed: 'AudioManager' has no member 'setEngineAvailability' — that API
is only on unreleased/main docs, not in the resolved LiveKitClient 2.15.3. Use the
API that actually ships (per audio.md): disable LiveKit's automatic AVAudioSession
configuration (AudioManager.shared.audioSession.isAutomaticConfigurationEnabled =
false) and configure the session ourselves in CXProvider didActivate. Removed all
setEngineAvailability(.none/.default) calls.

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

mobile/plugins/native-call/NativeCall.podspec

@@ -18,8 +18,9 @@ Pod::Spec.new do |s|
   s.ios.deployment_target = '14.0'
   s.dependency 'Capacitor'
   # LiveKit iOS SDK — carries the call media NATIVELY so audio survives backgrounding AND coordinates with
-  # CallKit's audio session (AudioManager.setEngineAvailability on didActivate/didDeactivate), which the
-  # WebView's WebRTC could not do. Pulls in the WebRTC binary transitively.
+  # CallKit's audio session (auto-config OFF via AudioManager.shared.audioSession.isAutomaticConfigurationEnabled;
+  # we configure the session in CXProvider didActivate), which the WebView's WebRTC could not do. Pulls in the
+  # WebRTC binary transitively.
   s.dependency 'LiveKitClient', '~> 2.0'
   # CallKit + PushKit + AVFoundation are system frameworks (no external pod).
   s.frameworks = 'CallKit', 'PushKit', 'AVFoundation'

mobile/plugins/native-call/ios/Sources/NativeCallPlugin/NativeCallPlugin.swift

@@ -55,12 +55,12 @@ public class NativeCallPlugin: CAPPlugin, CAPBridgedPlugin, PKPushRegistryDelega
         registry.desiredPushTypes = [.voIP]
         pushRegistry = registry
 
-        // CallKit audio coordination. LiveKit auto-configures & activates the AVAudioSession by default, which
-        // RACES CallKit's own activation → intermittent dead mic / no audio, and the output route only settling
-        // once audio starts flowing (the "speaker turns on late" symptom). Fix (per LiveKit's CallKit guide):
-        // disable auto-config, keep the audio engine OFF, and start it ONLY inside CXProvider didActivate.
+        // CallKit audio coordination. LiveKit auto-configures the AVAudioSession by default, which RACES
+        // CallKit's own activation → intermittent dead mic / no audio + the output route only settling once
+        // audio starts flowing (the "speaker turns on late" symptom). Fix (per LiveKit's audio.md): turn OFF
+        // LiveKit's automatic session configuration and configure the session ourselves in CXProvider
+        // didActivate (when CallKit hands us the active session).
         AudioManager.shared.audioSession.isAutomaticConfigurationEnabled = false
-        try? AudioManager.shared.setEngineAvailability(.none)
     }
 
     // MARK: - LiveKit media
@@ -291,19 +291,19 @@ public class NativeCallPlugin: CAPPlugin, CAPBridgedPlugin, PKPushRegistryDelega
         action.fulfill()
     }
 
-    // CallKit owns the AVAudioSession lifecycle. Configure the session and START LiveKit's audio engine ONLY
-    // here (never before) — this is the fix for the intermittent dead mic / no-audio and late speaker routing.
+    // CallKit owns the AVAudioSession lifecycle. Since we disabled LiveKit's automatic configuration, configure
+    // the session HERE, when CallKit activates it — this is the fix for the intermittent dead mic / no-audio
+    // and late speaker routing (LiveKit's audio engine then runs on a correctly-configured, active session).
+    // Note: don't call setActive(true) — CallKit already activated it.
     public func provider(_ provider: CXProvider, didActivate audioSession: AVAudioSession) {
         do {
             try audioSession.setCategory(.playAndRecord, mode: .voiceChat, options: [.mixWithOthers])
-            try AudioManager.shared.setEngineAvailability(.default)
             notifyListeners("audioActivated", data: ["ok": true])
         } catch {
             notifyListeners("audioActivated", data: ["ok": false, "error": String(describing: error)])
         }
     }
     public func provider(_ provider: CXProvider, didDeactivate audioSession: AVAudioSession) {
-        try? AudioManager.shared.setEngineAvailability(.none) // stop the engine until the next call's didActivate
         notifyListeners("audioDeactivated", data: ["ok": true])
     }
 }