Commands validate by conditional responder attachment, so the cached
imagePayload decided whether ⌘V had a responder at all — and the one
pasteboard writer that never deactivates the app, the screenshot hotkey,
changed the pasteboard without any checkpoint firing. Menu validation is
now two concrete moments: a menu beginning to track, and ⌘ going down,
whose beat before the letter is when the observation re-arms the
responder. One changeCount read per check, no timers.
Claude-Session: https://claude.ai/code/session_014PtZdPwqZuqEDLc6wZMtEy