Display Annotation Author (Username) in Tooltip

**Why is this needed**: When hovering over or viewing an annotation in Grafana dashboards, the tooltip currently shows the annotation text, time range, and tags. However, it does not display who created the annotation. Adding the author’s username (or display name) would improve traceability and collaboration across teams. **What would you like to be added**: Make Author's username/id as configurable option in dashboard or global setting **Who is this feature for?** For everyone in collaborative environments. Currently, it is impossible for user to tell who added a specific annotation without knowing how to query the API Displaying the username in the annotation tooltip would: - Provide better auditability and context. - Allow teams to follow up directly with the annotation author.