fix: address remaining code review feedback

- Narrow generic catch clauses in .NET command/elicitation handlers
  with 'when (ex is not OperationCanceledException)' filter
- Remove redundant null-conditional (val?.ToString -> val.ToString)
  in SelectAsync and InputAsync switch expressions
- Add explanatory comments to Python empty except blocks

Author: MRayermannMSFT

dotnet/src/Session.cs

@@ -698,8 +698,10 @@ await handler(new CommandContext
             });
             await Rpc.Commands.HandlePendingCommandAsync(requestId);
         }
-        catch (Exception error)
+        catch (Exception error) when (error is not OperationCanceledException)
         {
+            // User handler can throw any exception — report the error back to the server
+            // so the pending command doesn't hang.
             var message = error.Message;
             try
             {
@@ -730,9 +732,9 @@ private async Task HandleElicitationRequestAsync(ElicitationRequest request, str
                 Content = result.Content
             });
         }
-        catch (Exception)
+        catch (Exception ex) when (ex is not OperationCanceledException)
         {
-            // Handler failed — attempt to cancel so the request doesn't hang
+            // User handler can throw any exception — attempt to cancel so the request doesn't hang.
             try
             {
                 await Rpc.Ui.HandlePendingElicitationAsync(requestId, new SessionUiHandlePendingElicitationRequestResult
@@ -827,7 +829,7 @@ public async Task<bool> ConfirmAsync(string message, CancellationToken cancellat
                 {
                     string s => s,
                     JsonElement { ValueKind: JsonValueKind.String } je => je.GetString(),
-                    _ => val?.ToString()
+                    _ => val.ToString()
                 };
             }
             return null;
@@ -859,7 +861,7 @@ public async Task<bool> ConfirmAsync(string message, CancellationToken cancellat
                 {
                     string s => s,
                     JsonElement { ValueKind: JsonValueKind.String } je => je.GetString(),
-                    _ => val?.ToString()
+                    _ => val.ToString()
                 };
             }
             return null;

python/copilot/client.py

@@ -2265,11 +2265,11 @@ def terminate(self):
                 try:
                     self.stdin.close()
                 except OSError:
-                    pass
+                    pass  # Safe to ignore — socket may already be closed
                 try:
                     self._socket.close()
                 except OSError:
-                    pass
+                    pass  # Safe to ignore — socket may already be closed
 
             def kill(self):
                 self.terminate()