Code-review 2026-05-20 sweep: re-review at 1cd51bb, resolve 72 findings across all 11 modules

Re-reviewed every module/client against the 10-category checklist
(REVIEW-PROCESS.md) at commit 1cd51bb, filed 72 new findings, and
fixed them in three priority waves (3 High, 17 Medium, 52 Low).

Highs
- Server-017: enumerate AcknowledgeAlarm / QueryActiveAlarms in
  GatewayGrpcScopeResolver so non-admin keys can use them; document
  the mapping in docs/Authorization.md; add interceptor tests.
- Client.Java-013: add the five missing bulk-method stubs to the
  CLI FakeSession so the test module compiles on a clean tree.
- Client.Rust-013: fix the clippy::doc_lazy_continuation regression
  in generated tonic code by reformatting the ReadBulkCommand proto
  comment and scoping a #![allow(...)] to the generated submodules.

Mediums (highlights)
- Server: unify GatewaySession state-lock discipline (-015) and
  make DisposeAsync race-safe against in-flight CloseAsync (-016);
  add constraint-enforcement test coverage for the bulk-plan path
  (-021).
- Worker: introduce StaRuntimeShutdownException so RunAlarmPollLoop
  can distinguish graceful shutdown from a real STA-affinity
  violation (-016); have the watchdog skip StaHung while
  CurrentCommandCorrelationId is non-empty so a legitimate slow
  ReadBulk no longer self-faults (-017).
- Tests: add per-method round-trip + cancellation coverage for the
  11 GatewaySession bulk methods (-013); replace the real TCP probe
  in GalaxyHierarchyCacheTests with an IGalaxyRepository fake
  (-016).
- IntegrationTests: drive the StreamEvents writer in the live Write
  test and assert OnWriteComplete (-012); add live tests for
  Unadvise/RemoveItem/Unregister ordering, WriteSecured, and
  abnormal worker exit (-014).
- Worker.Tests: replace MxAccessSession reflection with an internal
  CreateForTesting factory (-016); cover WorkerCancel and
  unexpected-body envelope branches (-017).
- Client.Java: cancel MxEventStream when close() races
  beforeStart() (-014); return a CancellingCompletableFuture that
  actually forwards cancellation through .thenApply chains (-015).
- Client.Python: drop the silent localhost-plaintext downgrade in
  the CLI; require explicit --plaintext (-013).
- Client.Rust: stop bench-read-bulk from polluting success-latency
  histograms with failed-call durations (-015); add coverage for
  the five MalformedReply paths, the bulk-write helpers, the
  Error::Unavailable mapping, and the unary-fault path (-016).
- Contracts: extend docs/Contracts.md with the bulk read/write
  command family (-009).

Lows (highlights)
- Server: cap GalaxyGlobMatcher.RegexCache; align
  WorkerAlarmRpcDispatcher missing-session handling; drop the
  duplicate dashboard @page routes; refresh IAlarmRpcDispatcher
  XML doc.
- Worker: surface SetXmlAlarmQuery COM failures; remove dead
  subscriptionExpression / ExecutingCommand arms; preserve
  factory-supplied runtime sessions; split MxAlarmSnapshot.cs into
  three files.
- Tests: dispose the WebApplication in seven test classes; rebuild
  FakeWorkerProcess.WaitForExitAsync against a real TaskCompletion
  source; switch the heartbeat-expires test to ManualTimeProvider;
  add InvariantCulture to the remaining DateTimeOffset.Parse sites;
  document GalaxyFilterInputSafetyTests in GatewayTesting.md.
- IntegrationTests: comment fixes, RecordingServerStreamWriter
  IDisposable, class-level [Trait], single-source ZB default
  connection string.
- Worker.Tests: replace silent-return gating with LiveMxAccessFact
  so absent env vars SKIP not pass; PascalCase rename of probe
  [Fact]s; deterministic deadline test; new frame-protocol error
  tests; ComputeTransitions diff-coverage; relocate dev-rig probes
  to Probes/.
- Contracts: add round-trip coverage and per-field redaction /
  Galaxy-identifier comments to the protos.
- Client.Dotnet: introduce clients/dotnet/Directory.Build.props so
  TreatWarningsAsErrors / analysers apply; document
  DiscoverHierarchyOptions and IMxGatewayCliClient; require typed
  bulk-read handles in CLI; surface AcknowledgeAlarm transport
  faults through Translate().
- Client.Go: kill dead code in alarms_test / fakeGalaxyServer /
  runWriteBulkVariant; document the six new subcommands in
  writeUsage; drain galaxy-watch events on limit; switch io.EOF
  comparisons to errors.Is.
- Client.Java: shared shutdown helpers + new shutdownTimeout
  option; regex-based credential redaction; Long.toUnsignedString
  for uint64 sequence; doc fixes.
- Client.Python: combine duplicate imports; add coverage for
  _percentile / bench-read-bulk / MAX_AGGREGATE_EVENTS /
  _api_key_from_env; populate pyproject metadata and ship py.typed.
- Client.Rust: expose next_correlation_id() so CLI ping/close
  stop hard-coding correlation IDs; resync RustClientDesign.md
  with the current Session / Error surface and CLI subcommand set.

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

docs/Sessions.md

@@ -33,12 +33,19 @@ public void TransitionTo(SessionState nextState)
             return;
         }
 
+        if (_state is SessionState.Closing
+            && nextState is not SessionState.Closed
+            && nextState is not SessionState.Faulted)
+        {
+            return;
+        }
+
         _state = nextState;
     }
 }
 ```
 
-`Closed` is terminal and `Faulted` only allows a transition to `Closed`. This guards against late callbacks (worker exit, heartbeat timeout) re-animating a session that is already torn down.
+`Closed` is terminal, `Faulted` only allows a transition to `Closed`, and `Closing` only allows a transition to `Closed` or `Faulted`. This guards against late callbacks (worker exit, heartbeat timeout) re-animating a session that is already tearing down or torn down — once `CloseAsync` has set `Closing` under `_syncRoot`, no `TransitionTo(Ready)` from another thread can walk the session back to `Ready`. Both close-related writes (`Closing` and `Closed`) go through `_syncRoot` exactly like every other state write; `_closeLock` only serializes concurrent close attempts.
 
 ### SessionManager (ISessionManager)
 
@@ -184,7 +191,7 @@ Sessions open with `MxGateway:Sessions:DefaultLeaseSeconds` (default 1800) added
 
 ### Close
 
-`GatewaySession.CloseAsync` is serialized by a per-session `SemaphoreSlim` (`_closeLock`). It transitions to `Closing`, asks the worker client to shut down within `ShutdownTimeout`, and on success transitions to `Closed`. If `WorkerClient.ShutdownAsync` throws, the session falls back to `IWorkerClient.Kill` (forced close):
+`GatewaySession.CloseAsync` is serialized by a per-session `SemaphoreSlim` (`_closeLock`) so only one close runs at a time, but every read/write of `_state` still passes through `_syncRoot` (via `TryBeginClose` and `MarkClosed`). The close path therefore obeys the same lock discipline as `TransitionTo` / `MarkFaulted`: it transitions to `Closing`, asks the worker client to shut down within `ShutdownTimeout`, and on success transitions to `Closed`. `DisposeAsync` waits on `_closeLock` once before disposing the semaphore so an in-flight close's `Release()` cannot race against the dispose. If `WorkerClient.ShutdownAsync` throws, the session falls back to `IWorkerClient.Kill` (forced close):
 
 ```csharp
 if (_workerClient is not null)