feat: add queued status + FIFO queue ordering

- Add Queued variant to VideoStatus enum
- Trigger sets videos.status='queued' instead of staying 'pending'
- Worker sets videos.status='processing' on pickup
- list_monitor_jobs_by_status ORDER BY created_at ASC (FIFO)
- queue_position counts both 'pending' and 'queued' jobs

src/api/identities.rs

@@ -179,7 +179,7 @@ async fn list_identities(
         )
     })?;
 
-    let sql = format!(
+let sql = format!(
         "SELECT id::int, uuid, name, metadata FROM {} WHERE status IS NULL OR status != 'merged' ORDER BY id DESC LIMIT $1 OFFSET $2",
         id_table
     );