docs: complete XML-doc coverage and strip internal tracking IDs from code comments

Resolve all CommentChecker findings across the gateway server, worker, tests,
and .NET client (314 -> 0 real issues): add missing <returns>/<summary>/<param>
on public and test members, convert Stream/interface overrides to <inheritdoc/>,
and remove internal task/issue tracking IDs (SEC-*, IPC-*, WRK-*, GWC-*, TST-*,
Client.Dotnet-*) from shipped code documentation while preserving the design
rationale prose. Shipped comments should not carry internal bookkeeping, and
complete XML docs keep the analyzer/TreatWarningsAsErrors gate and generated API
docs clean. The 6 remaining flags are heuristic false positives (MD5, UTC-4,
capacity-1, near-1601) left intact so real documentation is not corrupted.

Claude-Session: https://claude.ai/code/session_01DMXXvNuPekkkrTEyPNxEkW

src/ZB.MOM.WW.MxGateway.Worker.Tests/Ipc/WorkerPipeSessionTests.cs

@@ -452,7 +452,7 @@ public sealed class WorkerPipeSessionTests
     /// <summary>
     ///     Verifies that a DrainEvents control command with <c>max_events = 0</c> is bounded by the
     ///     worker rather than draining the entire queue into one reply frame: the session passes a
-    ///     capped, non-zero maximum to the runtime session (IPC-04).
+    ///     capped, non-zero maximum to the runtime session.
     /// </summary>
     /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
@@ -743,7 +743,7 @@ public sealed class WorkerPipeSessionTests
     }
 
     /// <summary>
-    ///     WRK-01 regression: a long in-flight STA command that keeps pumping
+    ///     Regression test: a long in-flight STA command that keeps pumping
     ///     must NOT self-fault as <c>StaHung</c>, and its reply must still be
     ///     delivered. The real fix makes <c>StaRuntime.PumpPendingMessages</c>
     ///     refresh <c>LastActivityUtc</c> on every wait iteration, so a healthy