Update the embedded API snapshot and documentation for Typst 0.15 while keeping the 0.14.2 API and query fallback available as a legacy compatibility path.
Add CI smoke coverage for Typst 0.14.2 so version-neutral examples and legacy API lookup continue to work during the transition.
Add stable and upstream-main API channels, keep api.json as the stable alias,
and switch CI to export and update only api-main.* from the current Typst main
checkout.