Alerting: Alert rule annotations not properly passed to notification templates in Grafana v12.1.1

### What happened? Alert rule annotations configured through the UI are correctly stored in the database but are not being passed to notification templates. When I configure custom annotations (like `__dashboardUid__`, `__panelId__`, `dashboard_uid`, `panel_id`) in the "Configure notification message" section, they appear correctly in the database query results but remain empty when accessed in notification templates. Database query shows: ```json { "__dashboardUid__": "212f1875-9664-48a6-b1da-5fff2278c677", "__panelId__": "10", "dashboard_uid": "212f1875-9664-48a6-b1da-5fff2278c677", "panel_id": "10" } ``` But notification template output shows: === Alerts[0].Annotations 所有键值对 === - summary: Notification test === CommonAnnotations 所有键值对 === - summary: Notification test === 关键字段检查 === __dashboardUid__ (Alerts[0].Annotations): __panelId__ (Alerts[0].Annotations): dashboard_uid (Alerts[0].Annotations): panel_id (Alerts[0].Annotations): Only the default summary annotation appears in templates, all custom annotations are missing. ### What did you expect to happen? I expected the custom annotations configured in alert rules to be available in notification templates through: - (index .Alerts 0).Annotations.annotation_name - .CommonAnnotations.annotation_name The annotations should be passed from the database to the notification template engine so users can: - Create dynamic dashboard links in notifications - Pass custom metadata to notification systems - Use the "Link dashboard and panel" functionality effectively - Build flexible notification workflows ### Did this work before? no ### How do we reproduce it? 1. Create or edit a Grafana-managed alert rule 2. Navigate to "Configure notification message" section 3. Add custom annotations: - __dashboardUid__: 212f1875-9664-48a6-b1da-5fff2278c677 - __panelId__: 10 - dashboard_uid: 212f1875-9664-48a6-b1da-5fff2278c677 - panel_id: 10 …