Resolve all 33 medium-severity architecture review findings

Second slice of the 2026-09-09 whole-system review remediation
(docs/plans/2026-09-09-arch-review.md §10), on top of the High slice 146a1323.

Runtime/devices: SR-2 alarm on-trigger integration scope; SR-3 correlated NativeAlarmActor
subscribe retry; SR-4 immutable audited DB target; SR-5 ordered InstanceActor stop/flush;
SR-12 rehydration fence; SR-13 S&F gate recheck per delivery; DC-4 no OPC UA security
downgrade; DC-5 alarm snapshot for every new subscriber; ORCH-1 sync-dispose joins the pump.

Management/UI: MG-2 site scope on audit tree + Flow Debugger Replay; MG-3 stale-probe memo
removed; MG-4 server-owned bulk-deploy deadline; UI-5 sandbox runs in a killable child
process (new CentralUI.SandboxWorker project); UI-14 bounded sandbox output/IPC.

Edge/audit: EI-1 relay audit ownership; EI-2 SkipBodyCapture suppresses error text; EI-3/EI-11
error-field redaction + caps; EI-4 single relay deadline, pre-execution-only retry; EI-5
authenticated relay provenance; EI-10 body cap before audit read.

Persistence/contracts: DL-1 global Instance.UniqueName unique index + conflict translation;
DL-2 DataConnection protocol config encrypted at rest (migration
20260909203046_EnforceGlobalInstanceNamesAndProtectProtocolConfiguration — coordinated
central upgrade, old binaries cannot read protected rows); DL-3 bounded Replay paging;
DL-6 cross-site Overwrite of a deployed instance rejected; XC-4 proto descriptor contract test.

Config/hygiene: XC-1 central listener isolation by local port; XC-2/XC-3 inert SMTP + cron
keys removed from rig settings; CM-2 env2 bootstrap guard enabled; DC-6 deploy site exit code;
DC-7 notifier retries only explicit standby rejection; XC-5 ClusterClient purged from docs.

Gates recorded in the report: build 0/0, 9 397 passed / 0 failed, rig redeployed on all
eight nodes with the migration applied. 46 Low findings remain open.

.claude/skills/scadabridge-components/SKILL.md

@@ -13,7 +13,7 @@ The authoritative spec for each entry is `docs/requirements/Component-<Name>.md`
 2. Deployment Manager — Central-side deployment pipeline, system-wide artifact deployment, instance lifecycle.
 3. Site Runtime — Site-side actor hierarchy (Deployment Manager singleton, Instance/Script/Alarm Actors), script compilation, Akka stream.
 4. Data Connection Layer — Protocol abstraction (OPC UA, custom), subscription management, clean data pipe.
-5. Central–Site Communication — Akka.NET ClusterClient (command/control) + gRPC server-streaming (real-time data), message patterns, debug streaming.
+5. Central–Site Communication — Authenticated gRPC command/control in both directions + SiteStreamService server-streaming, token-gated HTTP configuration fetch, message patterns, debug streaming.
 6. Store-and-Forward Engine — Buffering, fixed-interval retry, parking, SQLite persistence, replication.
 7. External System Gateway — External system definitions, API method invocation, database connections.
 8. Notification Service — Central-only notification-list and SMTP definitions, per-type delivery adapters (sites no longer deliver notifications).
@@ -26,7 +26,7 @@ The authoritative spec for each entry is `docs/requirements/Component-<Name>.md`
 15. Host — Single deployable binary, role-based component registration, Akka.NET bootstrap.
 16. Commons — Shared types, POCO entity classes, repository interfaces, message contracts.
 17. Configuration Database — EF Core data access layer, repositories, unit-of-work, audit logging (IAuditService), migrations.
-18. Management Service — Akka.NET actor providing programmatic access to all admin operations, ClusterClientReceptionist registration.
+18. Management Service — Akka.NET actor providing programmatic access to all admin operations, authenticated HTTP Management API.
 19. CLI — Command-line tool using HTTP Management API, System.CommandLine, JSON/table output.
 20. Traefik Proxy — Reverse proxy/load balancer fronting central cluster, active node routing via `/health/active`, automatic failover.
 21. Notification Outbox — Central component ingesting store-and-forwarded notifications, `Notifications` audit table, dispatcher loop, retry/parking, delivery KPIs.