* Add craft-figma-rest: a typed model of the Figma REST file JSON
The neutral model for design files: the .fig and .sketch readers map onto
it and an application's importer takes it. Typed records for the document
tree, paints, effects, text styles, layout grids, constraints, export
settings and the component and style metadata; every record keeps the
fields it has no name for, so a file read and written loses nothing.
The vectorNetwork extension is typed and documented with the others.
The layer tree is converted level by level in both directions, and the
depth and node limits are checked on the JSON before any typed value is
built.
* craft-figma-rest: Warnings and style_name for the readers that build this shape
Moved from FigCraft's REST importer and .fig reader (crates/format/src/rest.rs
Warnings, fig.rs style_name), which the .fig and Sketch mappings share.
