Set line creator if not already defined (#305)

Adds logic to assign the line's creator property to the user's agent if it is undefined when processing items. This ensures that the creator information is consistently set for new or updated lines.

Author: cubap

package-lock.json

@@ -99,6 +99,7 @@ router.route('/:pageId')
           const line = item.id?.startsWith?.('http')
             ? new Line(item)
             : Line.build(projectId, pageId, item, user.agent.split('/').pop())
+          line.creator ??= user.agent.split('/').pop()
           return await line.update()
         }))
       }