Pure decision function for whether to show the token usage warning for a session.
Callers are expected to short-circuit before invoking this when the warning feature
is disabled, so this helper is not concerned with the enabled state.
reset: usage is below the threshold; any prior "already notified" state for this session should be cleared.
skip: we already notified for this session while still above the threshold.
notify: warning should be shown now and the session marked as notified.
Pure decision function for whether to show the token usage warning for a session. Callers are expected to short-circuit before invoking this when the warning feature is disabled, so this helper is not concerned with the enabled state.
reset: usage is below the threshold; any prior "already notified" state for this session should be cleared.skip: we already notified for this session while still above the threshold.notify: warning should be shown now and the session marked as notified.