import_fuzz now also feeds garbage and mutated `.vcswatches`, `.gpl`,
`.vcstyles` and `.vcflattener` files through `swatch.library.load` /
`graphicStyle.loadLibrary` / `flattener.presets.import`, uses what loads
(adds and applies the swatches and styles, previews and flattens with the
presets) and renders and exports the result. The SVG generator gains `<a>`,
Lab colours, mask options (`mask-type`, `data-vectorcraft-mask`) and paint
attributes. `PROPTEST_CASES` now raises the case count as the file's docs
say (an explicit `cases: 64` used to override it).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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