build(ios): add LiveKitClient pod to native-call (native call media)

Foundation for native LiveKit calling: the LiveKit iOS SDK carries the call media
natively and coordinates its audio engine with CallKit's AVAudioSession (AudioManager
.setEngineAvailability on didActivate/didDeactivate) — the thing WebKit's WebRTC can't
do. With this, the CallKit call stays active (stable ring + lock-screen answer +
background) AND the mic works. Native connection code + server LiveKit token in the VoIP
payload + WebView coordination come next. Don't build yet.

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

mobile/plugins/native-call/NativeCall.podspec

@@ -17,6 +17,10 @@ Pod::Spec.new do |s|
   s.source_files = 'ios/Sources/**/*.{swift,h,m}'
   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.
+  s.dependency 'LiveKitClient', '~> 2.0'
   # CallKit + PushKit + AVFoundation are system frameworks (no external pod).
   s.frameworks = 'CallKit', 'PushKit', 'AVFoundation'
   s.swift_version = '5.1'