Function map_cursor_hook 

pub fn map_cursor_hook(payload: &Value) -> Option<(HookSignal, Option<String>)>

Map one cursor lifecycle-hook payload (the JSON the CLI pipes to the hook command’s stdin) to a signal and an optional human-readable detail. None = the event carries no status meaning for this lane and is IGNORED (malformed or unmapped payloads are always ignorable — the relay treats them as success and never retries).

The mapping is deliberately honest about what a headless --print session can produce:

• sessionStart → HookSignal::Running.
• stop → HookSignal::TurnFinished. In an INTERACTIVE cursor session a stop means “idle at the prompt”; kranz’s cursor backend is always headless single-shot (agent --print, see crate::backend_cursor module docs), where the agent stopping IS the turn finishing.
• sessionEnd → completed maps to HookSignal::TurnFinished; aborted / error / window_close / user_close map to HookSignal::Interrupted with the reason (and any error_message) as detail. An absent reason is unmapped — never guessed at.
• postToolUseFailure with failure_type == "permission_denied" → HookSignal::NeedsInput: a headless session wanted a capability its posture refused, which is exactly the “a human should look” signal this lane exists to surface. Other failure types (timeout/error) are ordinary tool noise, not status.