[mvilacad]

Closes #572

Stacked on #576 (until it lands, the diff against main includes its commits).

What ships

• 269-term design atlas (DS001-DS269, English) with category, definition, traits, audience, sectors, UX risk and mitigation, three heuristic 1-5 scales, status in 2026, 2027-2030 trend (an editorial projection), how standard the term is, and its references.
• /atlas/ browse with facets (category, status, trend, standardization, three score bands), search, URL-shareable filters and an announced result count; 269 term pages with when to use it and when not, risk, evidence (with what the sources do not support), the scales labelled heuristic, our recipes, a paste-in AI prompt, and a Limits box with the review date.
• Markdown twins: /llms/atlas.txt and /llms/atlas/<slug>.txt.
• MCP search_terms, get_term, get_reference from dist/atlas.json (offline).
• styleHref returns null until a /styles/<id>/ page exists (STYLE_PAGES is empty), so a term never links to a 404.
• llms-full stays under its cap; the atlas is reached through llms.txt.

Fail before, pass after

• astro check: readonly Term[] not assignable to Term[] on <AtlasBrowser>; prop typed readonly: 0 errors.
• lint:tokens: (max-width: 40rem) is off the breakpoint scale; now 599.98px: ok.
• mcp-atlas.test.ts (new) drives the real stdio server: tools registered, search and filter, id/slug/name lookup, reference excerpt and check date.

Verified

Unit tests for atlas, MCP, evidence rules; axe (dark, light, forced colors) on /atlas/ and a term page: pass. Pre-push validate: ok.

Left open

Linking terms to /styles/ pages waits on that PR (STYLE_PAGES).