Tests: stabilize shard-2 queue and channel state

src/process/command-queue.ts

@@ -254,6 +254,18 @@ export function clearCommandLane(lane: string = CommandLane.Main) {
   return removed;
 }
 
+/**
+ * Test-only hard reset that discards all queue state, including preserved
+ * queued work from previous generations. Use this when a suite needs an
+ * isolated baseline across shared-worker runs.
+ */
+export function resetCommandQueueStateForTest(): void {
+  const queueState = getQueueState();
+  queueState.gatewayDraining = false;
+  queueState.lanes.clear();
+  queueState.nextTaskId = 1;
+}
+
 /**
  * Reset all lane runtime state to idle. Used after SIGUSR1 in-process
  * restarts where interrupted tasks' finally blocks may not run, leaving