docs: deferred-table closure, stale-comment sweep, as-built execution record

src/ZB.MOM.WW.MxGateway.Server/Sessions/SessionEventDistributor.cs

@@ -56,9 +56,9 @@ public delegate void SubscriberOverflowHandler(bool isOnlySubscriber, bool isInt
 ///         <see cref="Func{T, TResult}"/> producing an
 ///         <see cref="IAsyncEnumerable{T}"/> of already-mapped public
 ///         <see cref="MxEvent"/>s, given a <see cref="CancellationToken"/>. This is the
-///         cleanest seam: it can pass
-///         <c>ct =&gt; session.ReadEventsAsync(ct).Select(mapper.MapEvent)</c> (or a
-///         channel reader's <c>ReadAllAsync</c>), while unit tests pass a plain
+///         cleanest seam: production passes <c>GatewaySession.MapWorkerEventsAsync</c>,
+///         which reads the worker event channel and maps each frame in one iterator
+///         (inlining what used to be a read-then-<c>Select</c> chain), while unit tests pass a plain
 ///         channel reader's <c>ReadAllAsync</c> with no real session. The pump owns the
 ///         single consumption of this enumerable; fan-out happens on the public
 ///         <see cref="MxEvent"/> after mapping, mirroring today's
@@ -751,9 +751,9 @@ public sealed class SessionEventDistributor : IAsyncDisposable
         }
 
         // Disconnect ONLY this subscriber: it is already out of the fan-out set (removed above),
-        // so complete its channel with the overflow fault. Its gRPC reader's MoveNextAsync then
-        // throws the SessionManagerException, which EventStreamService surfaces to the client
-        // exactly as the pre-epic per-RPC overflow did. The pump and every other subscriber are
+        // so complete its channel with the overflow fault. EventStreamService consumes the channel
+        // directly, so its next WaitToReadAsync throws the SessionManagerException, which it surfaces
+        // to the client exactly as the pre-epic per-RPC overflow did. The pump and every other subscriber are
         // untouched. This runs even when the handler above threw — the subscriber must never be
         // left attached with an un-completed channel.
         subscriber.Channel.Writer.TryComplete(new SessionManagerException(

src/ZB.MOM.WW.MxGateway.Worker/Ipc/WorkerFrameWriter.cs

@@ -179,7 +179,9 @@ public sealed class WorkerFrameWriter
     /// remaining events are written, so a batch in flight does not delay a control frame's delivery.
     /// Every frame's "written and flushed before completion" contract is unchanged. An event batch that
     /// a control frame cuts into therefore pays one extra flush; an uninterrupted batch still pays
-    /// exactly one.
+    /// exactly one. Mixed passes are not exotic — command replies are Control priority too, so
+    /// sustained command traffic concurrent with event streaming can hit them routinely; the cost
+    /// stays bounded at one extra flush per class transition present in the pass.
     /// </summary>
     /// <param name="envelopes">Envelopes to write, in order.</param>
     /// <param name="priority">Scheduling priority for the whole batch.</param>