feat: Implement optimistic UI for agent availability toggle, add email and phone visibility toggles, and improve the logout process with immediate socket disconnection and best-effort API calls.

lib/features/agents/presentation/providers/agent_detail_provider.dart

@@ -433,6 +433,13 @@ class AgentDetailNotifier extends StateNotifier<AgentDetailState> {
     return success;
   }
 
+  void updateAvailability(bool isAvailable) {
+    if (state.agent == null) return;
+    state = state.copyWith(
+      agent: state.agent!.copyWith(isAvailable: isAvailable),
+    );
+  }
+
   Future<bool> cancelConnection() async {
     final requestId = state.connectionRequestId;
     if (requestId == null) return false;