Review checklist

CI checks the mechanical rules. Reviewers check what machines cannot:

Behaviour

• The PR implements exactly its roadmap step; requirements it touches are listed and active.
• New behaviour has conformance cases, including degenerate inputs and each new diagnostic.
• Golden changes are explained and expected (label golden-change + changelog line).
• No silent fallback: every degraded path emits a coded diagnostic.

Design

• Code sits in the right crate (where does my code go?).
• Types make invalid states unrepresentable; functions are total.
• Loops over data charge the budget; recursion is bounded.
• Modules have one job; names say what things are in embroidery terms.

Provenance

• Nothing was copied, pasted or transliterated from Ink/Stitch or other GPL/AGPL code; behaviour is in the design docs in our own words.
• New data tables (palettes, format constants) cite their source.

Docs and UX

• User-facing docs updated in this PR; help text in the registry reads well for an embroiderer.
• New prose follows the writing style, and cargo xtask prose passes.
• Shots refreshed if pictures should change; alt text is meaningful.
• Messages are specific, actionable and free of internal jargon.

Machine

• If the change affects what sews, it is listed for the next machine checkpoint.