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.Server/Security/Authorization/GatewayGrpcAuthorizationInterceptor.cs

@@ -64,7 +64,7 @@ public sealed class GatewayGrpcAuthorizationInterceptor(
 
         string? authorizationHeader = context.RequestHeaders.GetValue("authorization");
 
-        // SEC-11: short-circuit a peer that has already failed too many times inside the sliding
+        // Short-circuit a peer that has already failed too many times inside the sliding
         // window BEFORE the verification store read, so online guessing cannot spend a SQLite read
         // per attempt. The peer key prefers the presented key id over the transport address (NAT
         // caveat). ResourceExhausted signals throttling without revealing whether any particular