* refactor!: register HTML and Tailwind JSX as IO formats
HTML and Tailwind JSX went around the IO registry: the CLI appended
`html` to its format list and had its own HTML and Tailwind export paths,
so the app's export options offered neither.
Core now registers `html` and `tailwind-jsx` adapters built on a new
browser-safe `@open-pencil/dom-css/export` entry. Export results can
carry assets written next to the main file, which covers standalone HTML
with external images and fonts, and the CLI writes every format the same
way. The CSS object model and Node file access load only when an export
needs them, so the app bundle stays free of the headless CSS runtime.
BREAKING CHANGE: `sceneNodesToTailwindJSX` and `designDocumentToTailwindJSX`
moved from `@open-pencil/dom-css/browser` to `@open-pencil/dom-css/export`.
* refactor(core): share export support and fixed-size options across IO formats
Five adapters export every target and six have no scale or quality
options; the new HTML and Tailwind JSX adapters repeated those blocks
again. Both are now named once and shared.
* fix(core): keep HTML asset paths relative for Windows output paths
The CLI passed the absolute output path as the export file name, and the
HTML adapter only split it on `/`, so on Windows the page referenced
absolute `C:\...\card.assets` paths and assets were written to a doubled
location. The CLI now passes the file name, and the adapter accepts
either separator.
