fn resolve_idle_secs(
backoff: &mut IdleProbeBackoff,
probe: impl FnOnce() -> Result<u64, String>,
) -> Option<u64>Expand description
Resolve this tick’s raw idle seconds, driving the probe back-off.
probe performs the platform UserIdle call, yielding the idle
seconds on success or a display-error string on failure. The back-off
state and the throttled warning are handled here; the only thing the
caller keeps platform-bound is probe itself, so this decision logic
is unit-testable without a windowing system.
A failed or skipped (in-cooldown) probe reports None — idle is
unknown this tick. Callers map that to 0 (“active”) for screen-time
and idle-suppression (the conservative default that never silently
suppresses a break), but the typing-defer path treats None as “can’t
tell” and fires rather than stalling every break for the cap (#67).