The scene's ui.kiosk, or null/undefined when it has none.
Untrusted shape: a store is a file someone downloaded, so a non-boolean
field falls back rather than being coerced.
Whether ?kiosk was present.
When kiosk mode is on, the restrictive defaults apply to every field the
author did not set — that is the point of the switch. An author who wants a
locked display that still takes touch says allow_pointer=True explicitly.
Resolve kiosk mode from the authored block and the URL flag.