ACP: a preToolUse hook's ask is denied by host policy instead of reaching the client #5396

Copilot CLI 1.0.108, copilot --acp, driven by an ACP client, in its approval-required mode (it doesn't approve everything automatically). A preToolUse hook returns permissionDecision: "ask". The session events show permission.requested of kind hook, completed 1 ms later as denied-interactively-by-user with decisionSource: host_policy. The client never receives a session/request_permission. Shell and write requests in the same session do reach the client (human_response). Expected: forward a hook ask to the ACP client like other permission requests, or document that ACP cannot show one.