feat(runtime): PeerOpcUaProbeActor real TCP-connect probe (F12)

Replaces the Ok=true stub with a TCP connect to the peer's OPC UA port (4840
default) with a 2s timeout. A successful connect indicates the OPC UA server
process is up + accepting connections — enough for the redundancy calculator
to treat the peer as live. A full secure-channel Hello/Acknowledge handshake
is overkill for what the redundancy calc consumes and would pull in the OPC
UA Client SDK + a PKI setup. Upgrade later if a deeper liveness signal is ever
required.

Probe extracts the host from NodeId by stripping the :port suffix (commit
5cfbe8b encoded host:port into NodeId for cluster-member identity).

Tests: 2 new tests — Ok=true against a live TcpListener on a chosen port,
Ok=false against an unreachable endpoint. All 17 Runtime tests pass (was 16
covering only the message-contract surface).

docs/plans/2026-05-26-akka-hosting-alignment-plan.md.tasks.json

@@ -77,8 +77,8 @@
     {"id": 65, "subject": "Task 65: New v2 docs (Architecture-v2, Cluster, ControlPlane, Runtime)", "status": "completed", "classification": "standard", "estMinutes": 5, "parallelizableWith": [62,63,64], "blockedBy": [57], "commit": "1689901"},
     {"id": "F1", "subject": "Follow-up: AuthEndpoints integration tests against fused Host", "status": "completed", "classification": "small", "estMinutes": 10, "parallelizableWith": ["F2"], "blockedBy": [53], "commit": "463512d", "origin": "Deviation from Task 29 (commit 38ea0c5) — deferred until Task 53 wires AddOtOpcUaAuth/MapOtOpcUaAuth in Program. Add WebApplicationFactory<OtOpcUa.Host.Program> tests for /auth/login (204/401/503), /auth/ping (401/200), /auth/token (200+JWT), /auth/logout (204+cookie clear) using a stub ILdapAuthService.", "deviation": "Used HostBuilder + TestServer directly (Security.Tests/AuthEndpointsIntegrationTests) instead of WebApplicationFactory<Program> — Host needs Akka cluster bootstrap that's out of scope for this contract test. Cluster-mode auth coverage belongs in Task 58."},
     {"id": "F2", "subject": "Follow-up: Replace JwtBearer BuildServiceProvider antipattern with IPostConfigureOptions", "status": "completed", "classification": "small", "estMinutes": 5, "parallelizableWith": ["F1"], "blockedBy": [], "commit": "45a8c79", "origin": "Deviation from Task 26 (commit 207fc6a) — AddOtOpcUaAuth uses services.BuildServiceProvider().CreateScope() inside .AddJwtBearer lambda (ASP0000). Refactor to IPostConfigureOptions<JwtBearerOptions> so validation parameters resolve lazily from the real request provider."},
-    {"id": "F3", "subject": "Follow-up: Add EventId unique column to ConfigAuditLog for cross-restart audit idempotency", "status": "pending", "classification": "small", "estMinutes": 15, "parallelizableWith": ["F4"], "blockedBy": [], "origin": "Deviation from Task 33 — AuditWriterActor only dedups in-buffer; ConfigAuditLog lacks EventId column so a duplicate AuditEvent that arrives after a flush becomes a duplicate row. Add nullable EventId Guid + filtered unique index, migration, and refactor AuditWriterActor.WrapDetails away."},
-    {"id": "F4", "subject": "Follow-up: Harden AuditWriterActor.WrapDetails JSON synthesis with System.Text.Json", "status": "pending", "classification": "small", "estMinutes": 5, "parallelizableWith": ["F3"], "blockedBy": [], "origin": "Self-review of Task 33 — WrapDetails uses string concat; malformed caller DetailsJson would produce invalid JSON and trip the CK_ConfigAuditLog_DetailsJson_IsJson constraint, killing the entire flush batch. Discard this task if F3 lands first (F3 removes WrapDetails entirely)."},
+    {"id": "F3", "subject": "Follow-up: Add EventId unique column to ConfigAuditLog for cross-restart audit idempotency", "status": "completed", "classification": "small", "estMinutes": 15, "parallelizableWith": ["F4"], "blockedBy": [], "commit": "f57f61d", "origin": "Deviation from Task 33 — AuditWriterActor only dedups in-buffer; ConfigAuditLog lacks EventId column so a duplicate AuditEvent that arrives after a flush becomes a duplicate row. Add nullable EventId Guid + filtered unique index, migration, and refactor AuditWriterActor.WrapDetails away."},
+    {"id": "F4", "subject": "Follow-up: Harden AuditWriterActor.WrapDetails JSON synthesis with System.Text.Json", "status": "completed", "classification": "small", "estMinutes": 5, "parallelizableWith": ["F3"], "blockedBy": [], "commit": "f57f61d", "deviation": "Moot — F3 deleted WrapDetails entirely (EventId/CorrelationId now live in dedicated columns).", "origin": "Self-review of Task 33 — WrapDetails uses string concat; malformed caller DetailsJson would produce invalid JSON and trip the CK_ConfigAuditLog_DetailsJson_IsJson constraint, killing the entire flush batch. Discard this task if F3 lands first (F3 removes WrapDetails entirely)."},
     {"id": "F5", "subject": "Follow-up: ConfigPublishCoordinator multi-node happy-path test", "status": "pending", "classification": "standard", "estMinutes": 30, "parallelizableWith": [], "blockedBy": [], "origin": "Self-review of Task 30 — single-ActorSystem TestKit can't simulate the plan's 'dispatch to N driver nodes, all ack, seals' happy path because DiscoverDriverNodes() needs real cluster membership. Add a multi-system test (two ActorSystems joined into one cluster, driver-role on the second)."},
     {"id": "F6", "subject": "Follow-up: RedundancyStateActor publisher abstraction so tests don't need DPS bootstrap", "status": "completed", "classification": "small", "estMinutes": 10, "parallelizableWith": [], "blockedBy": [], "commit": "dfc143c", "origin": "Self-review of Task 35 — RedundancyStateActorTests are skipped because single-node DistributedPubSub bootstrap is unreliable in TestKit. Inject an Action<object> broadcast so tests can replace it with a probe; un-skip both tests."},
     {"id": "F7", "subject": "Follow-up: DriverInstanceActor full engine wiring (subscriptions, writes, ApplyDelta diff)", "status": "pending", "classification": "standard", "estMinutes": 45, "parallelizableWith": [], "blockedBy": [44], "origin": "Self-review of Task 41 — subscription publishing, ApplyDelta diffing, bad-quality-on-disconnect, write path, and supervisor backoff are stubbed. Wire after OpcUaPublishActor lands."},