Acknowledge a digital output write with its queue index

The controller queues the write; the acknowledgement policy still filed
it with the system commands, so the client answered 1 for it instead of
the index the queue assigned.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N8zt66KjkzgZLtQuSfJd9r

Author: claude

parol6/ack_policy.py

@@ -11,7 +11,6 @@
     CmdType.SIMULATOR,
     CmdType.SELECT_PROFILE,
     CmdType.RESET_STATE,
-    CmdType.WRITE_IO,
     CmdType.SET_TCP_OFFSET,
     CmdType.SET_SHAPES,
     CmdType.SET_STATUS_RATE,
@@ -63,6 +62,7 @@
     CmdType.SELECT_TOOL,
     CmdType.DELAY,
     CmdType.CHECKPOINT,
+    CmdType.WRITE_IO,
     CmdType.TOOL_ACTION,
 }