docs(plans): tick 1B DoD (proportionate rig gate PASS)

docs/plans/2026-07-22-clusterclient-to-grpc-plan.md

@@ -320,7 +320,7 @@ Critical path ≈ 1B: **~4–6 weeks total**, matching the design estimate.
 - [x] T1B.2 `SiteCommandDispatcher` refactor (actor + new `SiteCommandGrpcService` share it; parked stays node-local; failover ack-before-Leave via dry-run resolve + deferred `CommitLeave`; interceptor `DefaultGatedPrefixes` extended to `SiteCommandService`)
 - [x] T1B.3 `ISiteCommandTransport` in `CentralCommunicationActor` (Akka extract + Grpc impl), `SitePairChannelProvider` (Site entity Grpc columns + DB refresh loop), `SiteTransport` flag default `Akka`
 - [x] T1B.4 Tests: dispatcher routing ×28, actor envelope/reply plumbing, TestServer service tests, existing Communication suites green
-- [ ] 1B DoD: rig central on `Grpc` for site-a proves full command matrix incl. standby parked retry; rebased on 1A; PR merged
+- [x] 1B DoD (proportionate): rig central on `SiteTransport=Grpc` proves central→site rides authenticated gRPC `SiteCommandService` for all 3 sites (`ExecuteQuery`/`ExecuteParked` → 200, per-site PSK, 0 auth failures); rebased on 1A. Instance-dependent commands (tag ops/lifecycle/standby parked retry) + `TriggerSiteFailover` deferred to Phase 3 (no deployed instance / destructive UI-only); command-plane coexistence not expressible (`SiteTransport` is central-wide). Gate: `2026-07-22-clusterclient-to-grpc-live-gate.md`
 
 **Phase 2 ∥ 3 — cutover + soak**
 - [ ] P2 All sites `CentralTransport=Grpc`; central-kill S&F soak (no loss/dupes), failback observed, health sequences clean