Implement collection item reordering with bulk operations and persistent HTML attributes

- Add bulk reorder API endpoint (PUT /api/collections/{id}/reorder) with atomic transactions
- Replace individual position updates with efficient bulk operations in frontend
- Implement unified ID generation and proper data-item-id injection during enhancement
- Fix collection item position persistence through content edit cycles
- Add optimistic UI with rollback capability for better user experience
- Update sqlc queries to include last_edited_by fields in position updates
- Remove obsolete data-content-type attributes and unify naming conventions

internal/db/queries/collection_items.sql

@@ -38,7 +38,7 @@ RETURNING item_id, collection_id, site_id, template_id, html_content, position,
 
 -- name: UpdateCollectionItemPosition :exec
 UPDATE collection_items 
-SET position = sqlc.arg(position)
+SET position = sqlc.arg(position), updated_at = CURRENT_TIMESTAMP, last_edited_by = sqlc.arg(last_edited_by)
 WHERE item_id = sqlc.arg(item_id) AND collection_id = sqlc.arg(collection_id) AND site_id = sqlc.arg(site_id);
 
 -- name: ReorderCollectionItems :exec
@@ -47,6 +47,8 @@ SET position = position + sqlc.arg(position_delta)
 WHERE collection_id = sqlc.arg(collection_id) AND site_id = sqlc.arg(site_id) 
   AND position >= sqlc.arg(start_position);
 
+
+
 -- name: DeleteCollectionItem :exec
 DELETE FROM collection_items 
 WHERE item_id = sqlc.arg(item_id) AND collection_id = sqlc.arg(collection_id) AND site_id = sqlc.arg(site_id);