docs: strip task-tracking IDs from code comments and fill missing XML docs

Tracking IDs are review bookkeeping that rots in shipped source; the rationale they tagged is kept. Comment-only change (CommentChecker 458 -> 16 false positives).

src/ZB.MOM.WW.MxGateway.Server/Metrics/GatewayMetrics.cs

@@ -35,7 +35,7 @@ public sealed class GatewayMetrics : IDisposable
     private readonly ConcurrentDictionary<string, long> _eventsBySession = new(StringComparer.Ordinal);
     private readonly Dictionary<string, long> _retryAttemptsByArea = new(StringComparer.OrdinalIgnoreCase);
 
-    // GWC-15: live backlog sources for the gRPC event-stream queue-depth gauge. Each active
+    // live backlog sources for the gRPC event-stream queue-depth gauge. Each active
     // StreamEvents subscriber registers a delegate returning its channel's current backlog; the
     // gauge sums them ONLY when scraped or projected (GetGrpcEventStreamQueueDepth), so nothing is
     // read on the per-event streaming hot path. Concurrent because subscribers register/unregister
@@ -43,7 +43,7 @@ public sealed class GatewayMetrics : IDisposable
     private readonly ConcurrentDictionary<long, Func<int>> _eventStreamBacklogSources = new();
     private long _nextEventStreamBacklogSourceId;
 
-    // PERF-02: the same pull model for the worker event queue depth. It replaces a pushed scalar that
+    // the same pull model for the worker event queue depth. It replaces a pushed scalar that
     // every WorkerClient wrote twice per event (staged, consumed) under _syncRoot — a process-wide
     // lock on the hottest path, and last-writer-wins across sessions, so the gauge reported one
     // arbitrary session's backlog instead of the gateway's. Each client registers a source returning
@@ -210,7 +210,7 @@ public sealed class GatewayMetrics : IDisposable
     /// <param name="method">Name of the command method.</param>
     public void CommandStarted(string method)
     {
-        // PERF-02: the three command counters run two-to-three times per gRPC call, so they use
+        // the three command counters run two-to-three times per gRPC call, so they use
         // Interlocked rather than _syncRoot — the same idiom as EventReceived. Nothing here needs a
         // consistent multi-field view; GetSnapshot reads each with Interlocked.Read.
         Interlocked.Increment(ref _commandsStarted);
@@ -281,7 +281,7 @@ public sealed class GatewayMetrics : IDisposable
     ///     Registers a live depth source for the worker event queue-depth gauge and returns a handle
     ///     that removes it when disposed. Each <c>WorkerClient</c> registers once and reports its own
     ///     undelivered (staged + queued) event count, so the gauge is the gateway-wide sum instead of
-    ///     the last value any one session happened to push (PERF-02).
+    ///     the last value any one session happened to push.
     /// </summary>
     /// <param name="depth">
     ///     Returns this worker client's current undelivered event count. Invoked only at collection
@@ -303,7 +303,7 @@ public sealed class GatewayMetrics : IDisposable
     ///     returns a handle that removes it when disposed. The gauge sums every registered
     ///     source's current value on demand (when scraped or via <see cref="GetSnapshot"/>),
     ///     rather than tracking a pushed running total, so the streaming hot path does no
-    ///     per-event gauge bookkeeping (GWC-15).
+    ///     per-event gauge bookkeeping.
     /// </summary>
     /// <param name="backlog">
     ///     Returns this subscriber's current channel backlog. Invoked only at collection time;
@@ -351,7 +351,7 @@ public sealed class GatewayMetrics : IDisposable
     {
         // Tagged by stage only. Neither the key id nor the peer address may become a tag: key ids
         // are credential material and peer addresses are unbounded cardinality, and /metrics is not
-        // authenticated (open SEC-14), so anything tagged here is world-readable.
+        // authenticated, so anything tagged here is world-readable.
         _authThrottledCounter.Add(1, new KeyValuePair<string, object?>("stage", stage));
     }
 
@@ -460,7 +460,7 @@ public sealed class GatewayMetrics : IDisposable
     {
         // Compute the live queue depths outside _syncRoot: the sources are the subscriber channels'
         // Count (their own locks) and the worker clients' interlocked counters, neither of which may
-        // run under this lock. GWC-15, PERF-02.
+        // run under this lock.
         int workerEventQueueDepth = GetWorkerEventQueueDepth();
         int grpcEventStreamQueueDepth = GetGrpcEventStreamQueueDepth();
         lock (_syncRoot)
@@ -521,7 +521,7 @@ public sealed class GatewayMetrics : IDisposable
         }
     }
 
-    // Sums the undelivered event backlog across every live worker client (PERF-02).
+    // Sums the undelivered event backlog across every live worker client.
     private int GetWorkerEventQueueDepth() => SumSources(_workerEventQueueDepthSources);
 
     // Sums the live backlog across every registered event-stream subscriber.
@@ -571,6 +571,7 @@ public sealed class GatewayMetrics : IDisposable
     {
         private int _disposed;
 
+        /// <summary>Removes the source from its gauge; subsequent calls are no-ops.</summary>
         public void Dispose()
         {
             if (Interlocked.Exchange(ref _disposed, 1) == 0)