feat(pipeline): add InDesign style and design-token mapper

[PAMulligan]

Summary

Implements the Style and design-token mapper — sub-issue #65 of the InDesign-to-React epic (#62). It maps the IDML IR (from #63) to a coherent Aurelius design-token set and emits it in four formats, so generated components reference a real design system instead of inline magic numbers.

New token subsystem in packages/pipeline/src/tokens/, plus a gamut-aware convertColor in the IDML color module and a --emit-tokens CLI flow.

What the mapper does

• Colors — every swatch with a resolvable hex becomes a palette token, de-duplicated within a configurable sRGB tolerance; CMYK/Lab colors outside the sRGB gamut are flagged.
• Typography — paragraph styles are clustered into a heading / body / caption scale (largest sizes → top heading levels), preserving InDesign names. Font-size, line-height, and letter-spacing tokens share aligned keys.
• Spacing — paragraph spacing and indents are quantized to a configurable grid (default 4px) and named on a t-shirt scale.
• Fonts — families resolve to web font stacks via the configurable config/font-map.json; unmapped families fall back to a generic stack and emit a warning listed in the generator report.

Emitted artifacts

• tokens.ts — typed, self-contained (as const)
• tokens.css — :root custom properties
• tailwind.preset.ts — Tailwind v3+ preset exposing every token under theme.extend
• design-tokens.json — Style Dictionary compatible

node packages/pipeline/dist/indesign/cli.js brochure.idml --emit-tokens ./src/tokens

Acceptance criteria (#65)

• Generated tokens.ts type-checks under tsc --noEmit (verified via the TS compiler API) and validates against the published DesignTokensSchema
• Tailwind preset exposes every token; merge-into-config test confirms it
• Color palette includes all distinct swatches, deduped by hex within a configurable tolerance
• Font fallback warnings emitted and listed in the generator report
• Tests cover CMYK→sRGB against known values, paragraph-style clustering, and Tailwind preset merging

Testing

• pnpm --filter @aurelius/pipeline typecheck / test / build ✅ — 93 tests (41 new)
• Repo-wide eslint . (0 errors) and prettier --check . ✅
• check-doc-counts ✅; no dependency/lockfile changes
• Verified the compiled CLI emits all four artifacts on a real .idml, with config/font-map.json resolving correctly from dist/, out-of-gamut Lab flagged, and font fallbacks reported

Notes

• tokens.ts is self-contained by default (portable into any TS project); the library can also emit a satisfies DesignTokens form.
• Spacing is derived from paragraph spacing/indents; page margins and inter-frame gutters from layout geometry are noted as future work.

Closes #65
Part of #62

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