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

docs/WorkerFrameProtocol.md

@@ -136,7 +136,11 @@ cost stays bounded: a pure-event pass — the event hot path — still pays
 exactly one flush however many frames drain together, a run of control
 frames still pays one for the whole run (never one per heartbeat, the
 syscall-per-frame cost the coalescing removed), and only a pass that actually
-mixes both classes pays a second.
+mixes both classes pays a second. Mixed passes are not exotic: command replies
+travel at Control priority alongside heartbeats and faults, so a session under
+sustained command traffic concurrent with event streaming can hit them
+routinely. The cost stays bounded either way — one extra flush per class
+transition present in the pass, not per frame.
 
 One consequence of the boundary flush is worth stating: a control frame whose
 run has already been flushed and completed is out of the drain's