feat: background tasks panel (Phase 7)

Sources/LiveKit/VoiceSession.swift

@@ -33,6 +33,7 @@ final class VoiceSession: ObservableObject {
     let controlChannel = ControlChannel()
     let transcriptHandler = TranscriptHandler()
     let stateModel = ConversationStateModel()
+    let taskStore = TaskStore()
     let mediaController: MediaPlayerController
     private let config: ServerConfig
     private let tokenClient: TokenClient
@@ -71,6 +72,8 @@ final class VoiceSession: ObservableObject {
             selectedModel = model
             settings.modelID = model
             logger.log("model_changed applied: \(model, privacy: .public)")
+        case .taskEvent(let payload):
+            taskStore.apply(payload)
         default:
             break
         }