Maintenance submission uses owner-approved per-asset authorization.
An engineer must:
- Hold a valid credential in the configured engineer registry.
- Be explicitly authorized for the asset by the current asset owner through
authorize_engineer(owner, asset_id, engineer).
The owner can revoke this relationship with revoke_engineer_auth(owner, asset_id, engineer).
This prevents a credentialed engineer from submitting records for assets they have no owner-approved relationship with.