Modes & triggers

A guide is modal or passive.

• Modal: one at a time, veil and spotlight, scroll to the target, focus in the frame and restored at the end, global keyboard (Escape, arrows). Starting a second modal guide is refused unless you pass { replace: true }; a modal guide triggered automatically while another runs waits in a queue. Rendered by tour-frame and guide-spotlight.
• Passive: several at once, no veil, no scroll (a step waits until its target is in the viewport), no stolen focus; Escape only acts when the focus is inside the run's frame. Passive runs are suspended (hidden, state kept) while a modal run is active, and come back when it ends. Rendered by hint.

Triggers are "manual" (only start()) or "visible": the guide starts when the target of its first step (or of the step an in-progress record points at) becomes visible, if it is eligible and was never completed or dismissed.