Enriches the platform PLANE, not the kernel:
- DevOpaPort: the dev OPA stub now evaluates a small policy table (behind the
same opa.decide) — DM capped at 2, add-participant requires member/group-admin,
governed self-join for membership threads. Real OPA swaps in unchanged.
- Dev IdP login (POST /v1/dev/login) issues the same JWT claims a real IdP would.
- PolicyDeniedFilter maps fail-closed denials to HTTP 403.
Generic kernel additions (no chat vocabulary — 'dm'/'group' live only as OPA
policy + an opaque thread attribute):
- MessageService.addParticipant (governed membership by userId), governed
openThread self-join (scoped to threads with a membership attribute),
parentInteractionId on send (reply link), and a generic listThreads.
- REST: GET /v1/threads, POST /v1/threads, POST /v1/threads/:id/participants;
socket add_participant + membership/parentInteractionId. ensureParticipant
gains a role.
Tests: dev-opa.port.spec + message.spec (DM cap / group admin / governed join /
listThreads / reply). smoke-membership.mjs; realtime smokes updated for governed
join. 175 unit tests + all smokes green; kernel free of dm/group literals.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
