- All ARCHITECTURE §3 interfaces as pure types; dependency-free (no ws/node/DOM) so both backend and frontend can import it - Refinements vs §3 (documented): EnvLike (not NodeJS.ProcessEnv), WebSocketLike + WS_OPEN (not ws.WebSocket), added Config.wsPath (invariant 8) - ARCHITECTURE §3.1/§3.4 reconciled to match (anti-drift) - tsc --noEmit passes T2 of docs/PLAN.md