feat(designbook): technology-neutral IR + stack-adapter pipeline (WHYNOT-WP-0002 T01-T06)

Author the design language once in the canonical React designbook and project it
one-way onto each stack: React -> designbook/ -> ir/ -> adapters/<stack>/.

Phase 0 — contracts & governance (T01-T03):
- ir/SCHEMA.md + ir/schema/{component,tokens}.schema.json — neutral IR contract
  (W3C DTCG tokens; React prop -> HTML attribute mapping; non-portable props flagged).
- adapters/ADAPTER_CONTRACT.md — inputs, drift-report + parity-result shapes,
  idempotency rules, CI exit codes (0 ok / 2 usage / 3 drift / 4 parity / 5 internal).
- .claude/rules/designbook-propagation.md + DesignSystemIntroduction.md §5.1 —
  one-way directionality + drift-resolution workflow.

T04 — canonical React designbook + the missing pull tool:
- The bundled /design-sync skill only PUSHES repo->cloud; it cannot populate
  designbook/. Added scripts/designbook_pull.py + `make designbook-pull`, which drives
  the local claude binary headless (acceptEdits) so DesignSync fetch+write runs in a
  subprocess (contents never hit the orchestrator's context). Pulled 44 files;
  excludes the _whynot-design-seed/ self-copy. Corrected the docs that wrongly called
  /design-sync the pull.

T05 — IR extractor (scripts/ir-extract.mjs + `make ir`):
- ir/tokens.json (80 tokens, DTCG, var() -> {ref} alias resolution); ir/components/*.json
  (10 contracts parsed from .jsx signatures: enum/boolean/number inference, prop->attr
  map, style/callback marked non-portable); ir/exemplars/*.

T06 — Lit token adapter (adapters/lit/ + `make adapt-lit`):
- Full-gen tokens into src/styles/colors_and_type.css :root (marker-bounded, idempotent
  no-op on re-run; hand-authored type CSS preserved).

NOTE: token regen synced Lit to canonical React — fonts IBM Plex -> system stacks and 8
status tokens added. This is a VISUAL change: review and run `pnpm test:visual:update`
before merge. Remaining: T07 scaffold+drift, T08 parity, T09 runbook, T10 2nd-adapter.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -6,7 +6,34 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/). Version
 
 ## [Unreleased]
 
-_Nothing yet. Add entries above the next `[vX.Y.Z]` block as PRs land._
+### Added
+
+- **Technology-neutral IR + stack-adapter pipeline** (WHYNOT-WP-0002, Phase 0–3). The
+  design language is now authored once in the canonical React designbook and projected
+  one-way onto each stack: `React → designbook/ → ir/ → adapters/<stack>/`.
+  - `ir/` — committed, diffable blueprint: `ir/SCHEMA.md`, JSON Schemas
+    (`ir/schema/{component,tokens}.schema.json`), and the extractor's output
+    (`ir/tokens.json` in W3C DTCG format, `ir/components/*.json`, `ir/exemplars/*`).
+  - `adapters/ADAPTER_CONTRACT.md` — the contract every stack adapter implements
+    (inputs, drift report + parity result shapes, idempotency, CI exit codes).
+  - `scripts/designbook_pull.py` + `make designbook-pull` — pulls the React designbook
+    from Claude Design into `designbook/` (the bundled `/design-sync` skill only
+    *pushes*, so it cannot populate `designbook/`).
+  - `scripts/ir-extract.mjs` + `make ir` — extracts the IR from the `.jsx` ui-kit,
+    manifest, and previews.
+  - `adapters/lit/` + `make adapt-lit` — Lit reference adapter; tokens fully generated
+    into `src/styles/colors_and_type.css` (marker-bounded, idempotent).
+  - `.claude/rules/designbook-propagation.md` + `DesignSystemIntroduction.md` §5.1 —
+    one-way governance and drift-resolution workflow.
+
+### Changed
+
+- `src/styles/colors_and_type.css` — token `:root` block is now **generated** by
+  `make adapt-lit` from `ir/tokens.json` (between `@generated tokens` markers). This
+  synced the Lit token layer to the canonical React designbook: font stacks switched
+  from IBM Plex to system-font stacks, and the functional-status tokens
+  (`--status-error/warn/success/info` + `-bg`) were added. **Visual change — Playwright
+  baselines need review + `pnpm test:visual:update`.**
 
 ## [0.2.0] — 2026-05-25