Add designbook integration tooling + stack-adapter workplan

- designbook/ local mirror of the Claude Design project, with conventions
  (@dsCard/manifest) and freshness marker docs.
- make designbook-sync + scripts/designbook-sync.mjs: record what a sync
  changed into RecentChanges.md, grouped by layer, with last /design-sync time.
- make designbook-check + scripts/check_designbook_staleness.py: llm-connect
  (claude-code adapter) backend that detects when the cloud designbook moved
  ahead and warns the local mirror is outdated.
- .design-sync/config.json: recorded target project pin (WhyNot Design System).
- WHYNOT-WP-0002: workplan for a technology-neutral designbook IR with
  scaffold+drift-detect stack adapters (Lit reference).
- gitignore Python artifacts.

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

RecentChanges.md

@@ -0,0 +1,20 @@
+# Recent Changes
+
+Snapshot of the last designbook integration. Regenerated by `make designbook-sync`.
+
+- Generated: 2026-06-22T20:02:58Z
+- Compared: working tree (uncommitted)
+- Last /design-sync: never recorded
+
+> WARNING — no /design-sync has been recorded, so the local designbook/ may not
+> reflect the Claude Design project. Run `/design-sync` in Claude Code, then
+> `node scripts/designbook-sync.mjs --mark-synced`.
+
+> This file is overwritten on every run — a snapshot, not a log. Fold notable entries
+> into `CHANGELOG.md` under `## [Unreleased]` before releasing; that is the file CI
+> enforces (`pnpm check`). The designbook itself is synced via `/design-sync`, not this script.
+
+## Changed files
+
+### Designbook
+- `ADDED   ` designbook/README.md (+70 / -0)