[Improvement]Scheduled job for merge suggestions with UI configuration

[earayu]

To proactively generate graph merge suggestions, we need to implement a scheduled job that calls the /collections/{collection_id}/graphs/merge-suggestions endpoint.

This feature should include:

• A new section in the collection settings page to configure the scheduled job (enable/disable, set execution frequency).
• The frontend should only call this endpoint with force_refresh=false. This ensures that the UI uses the pre-generated suggestions from the scheduled job unless no suggestions currently exist.

[github-actions]

This issue has been marked as stale because it has been open for 30 days with no activity