Add bulk actions for held messages
Created by: DeeJayPee
- Add three bulk action buttons to held messages view:
- Delete All Held: Deletes all held messages
- Cancel All Held: Cancels hold on all held messages
- Release All Held: Releases all held messages for delivery
- Each action includes a confirmation dialog before execution
- Add corresponding routes and controller methods
- Add CSS styling for bulk actions section
- Display success message with count of affected messages