task-galaxy-e2e branch — non-FOCAS work-in-progress snapshot

Catch-all commit for pending work on the task-galaxy-e2e branch that
wasn't part of the FOCAS migration. Grouping by topic so future per-topic
commits can be cherry-picked if needed.

TwinCAT
- src/.../Driver.TwinCAT/AdsTwinCATClient.cs + TwinCATDriverFactoryExtensions.cs:
  factory-registration extensions + ADS client refinements.
- src/.../Driver.TwinCAT.Cli/Commands/BrowseCommand.cs: new browse command
  for the TwinCAT test-client CLI.
- tests/.../Driver.TwinCAT.IntegrationTests/TwinCAT3SmokeTests.cs + TwinCatProject/:
  fixture scaffold with a minimal POU + README pointing at the TCBSD/ESXi
  VM for e2e.
- docs/Driver.TwinCAT.Cli.md + docs/drivers/TwinCAT-Test-Fixture.md:
  documentation for the above.
- docs/v3/twincat-backlog.md: forward-looking backlog seed.

Admin UI + fleet status
- src/.../Admin/Components/Pages/Clusters/DriversTab.razor + Hosts.razor:
  UI refresh for fleet-status rendering.
- src/.../Admin/Hubs/FleetStatusHub.cs + FleetStatusPoller.cs +
  Admin/Program.cs: SignalR hub + poller plumbing for live fleet data.
- tests/.../Admin.Tests/FleetStatusPollerTests.cs: poller coverage.

Server + redundancy runtime (Phase 6.3 follow-ups)
- src/.../Server/Hosting/RedundancyPublisherHostedService.cs: HostedService
  that owns the RedundancyStatePublisher lifecycle + wires peer reachability.
- src/.../Server/Redundancy/ServerRedundancyNodeWriter.cs: OPC UA
  variable-node writer binding ServiceLevel + ServerUriArray to the
  publisher's events.
- src/.../Server/Program.cs + Server.csproj: hosted-service registration.
- tests/.../Server.Tests/ServerRedundancyNodeWriterTests.cs +
  Server.Tests.csproj: coverage for the above.

Configuration
- src/.../Configuration/Validation/DraftValidator.cs +
  tests/.../Configuration.Tests/DraftValidatorTests.cs: draft-validation
  refinements.

E2E scripts (shared infrastructure)
- scripts/e2e/README.md + _common.ps1 + test-all.ps1: shared helpers + the
  all-drivers test-all runner.
- scripts/e2e/test-opcuaclient.ps1: OPC UA Client e2e runner.

Docs
- docs/v2/implementation/phase-6-{1,2,3,4}*.md + exit-gate-phase-{3,7}.md:
  phase-gate + implementation doc updates.
- docs/v2/plan.md: top-level plan refresh.
- docs/v2/redundancy-interop-playbook.md: client interop playbook for the
  Phase 6.3 redundancy-runtime work.

Two orphan FOCAS docs remain on disk but deliberately unstaged —
docs/v2/focas-deployment.md and docs/v2/implementation/focas-simulator-plan.md
describe the now-retired Tier-C topology and should either be rewritten
or deleted in a follow-up.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/v2/implementation/phase-6-1-resilience-and-observability.md

@@ -1,6 +1,8 @@
 # Phase 6.1 — Resilience & Observability Runtime
 
-> **Status**: **SHIPPED** 2026-04-19 — Streams A/B/C/D + E data layer merged to `v2` across PRs #78-82. Final exit-gate PR #83 turns the compliance script into real checks (all pass) and records this status update. One deferred piece: Stream E.2/E.3 SignalR hub + Blazor `/hosts` column refresh lands in a visual-compliance follow-up PR on the Phase 6.4 Admin UI branch.
+> **Status**: **SHIPPED** 2026-04-19 — Streams A/B/C/D + E data layer merged to `v2` across PRs #78-82. Final exit-gate PR #83 turns the compliance script into real checks (all pass) and records this status update.
+>
+> **Stream E.2/E.3 closed 2026-04-23** — `FleetStatusPoller` now polls `DriverInstanceResilienceStatus`, detects per-`(DriverInstanceId, HostName)` deltas, and pushes `ResilienceStatusChangedMessage` via `FleetStatusHub` on the fleet group. Admin `/hosts` page subscribes on load and upserts the matching `HostStatusRow` in-memory on receipt, so operator-visible resilience state now reflects the runtime within one poller tick (~5 s) instead of the Admin page's own 10-second refresh. `FleetStatusPollerTests.Poller_pushes_ResilienceStatusChanged_on_delta` covers the first-observation push, the no-delta-no-push invariant, and the mutated-row re-push.
 >
 > Baseline: 906 solution tests → post-Phase-6.1: 1042 passing (+136 net). One pre-existing Client.CLI Subscribe flake unchanged.
 >
@@ -129,7 +131,7 @@ Closes these gaps flagged in the 2026-04-19 audit:
 - [ ] Stream B: Tier registry + generalised watchdog + scheduled recycle + wedge detector
 - [ ] Stream C: `/healthz` + `/readyz` + structured logging + JSON Serilog sink
 - [ ] Stream D: LiteDB cache + Polly fallback in Configuration
-- [ ] Stream E: Admin `/hosts` page refresh
+- [x] Stream E: Admin `/hosts` page refresh (E.1 in PRs #78-82 with the data layer; E.2/E.3 closed 2026-04-23)
 - [ ] Cross-cutting: `phase-6-1-compliance.ps1` exits 0; full solution `dotnet test` passes; exit-gate doc recorded
 
 ## Adversarial Review — 2026-04-19 (Codex, thread `019da489-e317-7aa1-ab1f-6335e0be2447`)