fix(channels): swallow rollback delete exceptions in auto-tune handler

DeleteSmartCollection rollback in CreateAutoTunedChannelsHandler.CreateOne
was called without exception handling; a transient infra exception during
the best-effort rollback would propagate and abort the whole batch,
contradicting the comment's stated intent. Wrap the send in try/catch so
an orphaned SmartCollection is the accepted degraded outcome instead.

ErsatzTV.Application/Channels/CreateAutoTunedChannelsHandler.cs

@@ -92,7 +92,17 @@ public class CreateAutoTunedChannelsHandler(ISender mediator)
             // Roll back the smart collection we just created so a retry of this
             // axis/value doesn't fail on SmartCollection-name uniqueness. Best-effort;
             // the primary outcome below is still Skipped/Failed regardless of the delete result.
-            await mediator.Send(new DeleteSmartCollection(smartCollection.Id), cancellationToken);
+            // Swallow any exception (not just an Either.Left) so a transient infra failure
+            // during rollback never aborts this channel's outcome or the batch; the
+            // orphaned SmartCollection is an acceptable degraded outcome.
+            try
+            {
+                await mediator.Send(new DeleteSmartCollection(smartCollection.Id), cancellationToken);
+            }
+            catch (Exception)
+            {
+                // intentionally ignored; see comment above
+            }
 
             AutoTuneOutcomeStatus status = error.Value.Contains(NumberTakenError, StringComparison.Ordinal)
                 ? AutoTuneOutcomeStatus.Skipped