Delete Learning User

Delete the learning records owned by a user. By default removes every learning type backed by the agno_learnings table (user_profile, user_memory, and any user-scoped entity records); pass learning_type to restrict deletion to a single store. Records with no owner (user_id IS NULL) are not affected. For a scoped (non-admin) caller, only their own learnings may be deleted; a different user_id is rejected with 403. Admins and unscoped callers may delete any user's learnings. Returns 204 even if the user had no matching records.