Address code review: log errors in StopAsync, remove redundant catch, document SessionManager

Co-authored-by: YimingZhanshen <76594627+YimingZhanshen@users.noreply.github.com>

Author: Copilot

AirPlay/Listeners/AirTunesListener.cs

@@ -446,7 +446,8 @@ public override async Task OnDataReceivedAsync(Request request, Response respons
                             // (ports 7002/7003 must be released first)
                             if (session.AudioControlListener != null)
                             {
-                                try { await session.AudioControlListener.StopAsync(); } catch { }
+                                try { await session.AudioControlListener.StopAsync(); }
+                                catch (Exception ex) { Console.WriteLine($"Error stopping old audio listener: {ex.Message}"); }
                                 session.AudioControlListener = null;
                             }
 

AirPlay/Listeners/MirroringListener.cs

@@ -134,10 +134,6 @@ public override async Task OnRawReceivedAsync(TcpClient client, NetworkStream st
                             session.SpsPps = spsPps;
                         }
                     }
-                    catch (OperationCanceledException)
-                    {
-                        break;
-                    }
                     catch (Exception e)
                     {
                         Console.WriteLine($"Mirroring error: {e}");

AirPlay/Services/SessionManager.cs

@@ -24,6 +24,11 @@ public Task<Session> GetSessionAsync(string key)
             return Task.FromResult(_session ?? new Session(key));
         }
 
+        /// <summary>
+        /// Store session state. Callers must always retrieve the session via GetSessionAsync first,
+        /// modify it, then save it back. The incoming session replaces the old one entirely,
+        /// allowing fields to be intentionally set to null (e.g., during TEARDOWN cleanup).
+        /// </summary>
         public Task CreateOrUpdateSessionAsync(string key, Session session)
         {
             _sessions.AddOrUpdate(key, session, (k, old) => session);