Checked individual TWT MAC action transport checkpoint on ns-3.48 Local acceptance: 142 test cases and both local-execution probes passed. 35 MAC transport cases cover actual Setup/response/Teardown traffic, association and HE role checks, malformed input, controlled PHY loss, MAC retries and lifecycle cleanup. Scope: ordinary individual actions on one associated QoS HE link, STA requester state and synchronous AP response metadata. Accept does not install executor agreements; Teardown does not automatically remove executing agreements. Coordinated execution, automatic TSF mapping, admission, application-level duplicate recovery, protected/broadcast TWT, MLO/EMLSR, OFDMA, energy validation and full-frame SP containment remain unsupported. An earlier MLO regression remains unresolved; see doc/twt/REGRESSION_STATUS.md.