Pin the mid-tool-call rule in the control board scanner (#1503)

Acceptance rule (plan page, bf641e22): a seat mid-tool-call is working,
never waiting. The scanner already met it through pi's stopReason values;
deriveState now also checks the content for a toolCall block (working),
after the error stop reasons and before "stop" (waiting). Thinking blocks
do not keep a text turn from being waiting. Three JSONL fixture tests and
three state-table cases pin the rule. Live check on the real board:
orch-01 and rev-code-01 mid-tool-call are working, velma's finished
text-only turn is waiting. Sonnet review: APPROVED.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

packages/control-board/README.md

@@ -11,8 +11,8 @@ rewritable; they are not run records and are not evidence.
 
 | State   | Plain-words meaning |
 |---------|----------------------|
-| working | The agent is in the middle of a turn: thinking or running a tool. |
-| waiting | The agent finished its turn. It is your move now. |
+| working | The agent is in the middle of a turn: thinking or running a tool. A seat whose newest log entry is a tool call or a tool result is working even if its last words looked like a question. |
+| waiting | The agent finished its turn with a text-only message. It is your move now. |
 | error   | The agent's last turn ended in an error, was aborted, or was cut off. Go look at it. |
 | offline | There is no live tmux session for this agent right now, or its session exists but no longer runs `pi`. |
 | idle    | The agent is live but has not had a conversation yet. |