The Export panel, SDK helpers, app menus, and CLI each kept their own
hand-written format lists, so new formats such as PPTX reached some
surfaces and not others.
Scene Graph now owns the persisted export-setting format ids, Core IO
adapters carry literal ids so that list is checked against real adapters,
and the panel labels, scale handling, app format types, and CLI format
validation/help are derived from the registry. PPTX joins the Export
panel as a result.
