Refuse list_agents after a parked director question is surfaced

[TheGreatAxios]

Summary

• After a parked ask_director is surfaced (TUI idle-send wake, nested wait_agents with a question payload, or a successful list_agents), further list_agents calls fail closed until send_input answers or the ask is dropped.
• First list may surface the question once; a new question_id is listable once. wait_agents stays mounted. Occupancy latch is unchanged.

Verification

• bun run typecheck, bun run build, and bun run test pass
• Targeted fleet tests pass under --randomize --seed 424242 (170 pass)
• bun run check (lint, typecheck, build, guarded suite: 6893 pass)

Fixes CL-7757

[linear-code]

CL-7757

[TheGreatAxios]

Critic · Comment

After a parked ask_director is surfaced, list_agents fails closed until send_input or the ask is dropped.

Findings

No blocking findings.

• src/subagent/agent-fleet.test.ts — close_agent and cancel are named clear-paths in CL-7757 but have no list_agents contract. interrupt_agent and send_input are covered; both close and cancel already drop the pending ask via settleCancelsAsks, so the gate should reopen, but that is inferred not tested.

Notes

• Runtime gate lives in createListAgentsTool, not prompt-only. Error names send_input, the worker session id, question_id, and the question text.
• First list surfaces once; identical snapshot errors; a new question_id is listable once. Yield wait does not stamp; TUI wake after sendInternalText does.
• wait_agents stays mounted. Occupancy latch / mailbox-mail-drive / fleet-dry-drive / settleRunToIdle are untouched. list_agents remains outside doom-loop poll exemption.