Fix missing ticker.Stop() in pollForSettingChanges (#1148)

The pollForSettingChanges function creates a ticker but never calls
Stop() on it when the context is cancelled, leaking the ticker's
internal runtime timer.

Other functions in the same file (heartbeatLogLoop, reportQueueStatusLoop)
correctly use defer ticker.Stop(). This aligns with that pattern.

Note: pollForSettingChanges only runs when no notifier is configured
(poll-only mode), so this only affects non-LISTEN/NOTIFY setups.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: GiGurra

producer.go

@@ -857,6 +857,7 @@ func (p *producer) pollForSettingChanges(ctx context.Context, wg *sync.WaitGroup
 	defer wg.Done()
 
 	ticker := time.NewTicker(p.config.QueuePollInterval)
+	defer ticker.Stop()
 	for {
 		select {
 		case <-ctx.Done():