The original single T17 (inbound method dispatch + ack plumbing) proved on a
2026-06-11 deep dive to be four hard problems: roles on the session identity
(T17), node-manager command router + AlarmAck veto + alarm-commands DPS topic
(T18), host-actor inbound handler (T19), and delta-gate double-emit (T20). Old
T18->T21 (AdminUI), old T19 split into T22 (Client.CLI feature) + T23 (verify),
old T20->T24. Adds the Layer 2 design-decisions preamble.
Joseph Doherty