chore: initial DSMMG v0.2 — refonte architecturale complète

Mise en place du Design System ManageMate Group v0.2 — refonte du
système de tokens (préfixe --mmg-color-*), 9 presets accent
user-themable validés WCAG AA, overlays Radix UI + Floating UI,
Storybook 8 + Vitest + axe-core en CI, doc Astro Starlight,
DESIGN.md (format google-labs-code) et exports tokens DTCG/CSS/
TS/Figma/Tailwind v3 et v4.

- 4 packages monorepo pnpm : @managemate/{tokens,css,react,icons}
- 62 composants React headless-first (Sheet, HoverCard, ContextMenu,
  Slider, ToggleGroup, AvatarGroup, UserCard, ProfileHeader,
  MetricCard, PricingCard, FeatureCard, Text/Display/Eyebrow/Lead…)
- Lint contraste WCAG : 37/37 paires AA, branché CI
- Toast pile Sonner-style avec ResizeObserver
- Theming user (9 presets) sans casser sémantique fixe
- Identité Synapse (rose #D12B6A) préservée

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package.json

@@ -0,0 +1,40 @@
+{
+  "name": "managemate-ds",
+  "private": true,
+  "version": "0.1.0",
+  "description": "ManageMate Group Design System (DSMMG) — monorepo",
+  "license": "UNLICENSED",
+  "workspaces": [
+    "packages/*",
+    "demo"
+  ],
+  "scripts": {
+    "build": "pnpm -r build",
+    "build:icons": "pnpm --filter @managemate/icons build",
+    "build:css": "pnpm --filter @managemate/css build",
+    "build:react": "pnpm --filter @managemate/react build",
+    "demo": "pnpm --filter demo dev",
+    "typecheck": "pnpm -r typecheck",
+    "test": "pnpm -r test",
+    "lint": "pnpm -r lint",
+    "storybook": "pnpm --filter storybook dev",
+    "build-storybook": "pnpm --filter storybook build",
+    "tokens:build": "pnpm --filter @managemate/css tokens:build",
+    "size": "size-limit",
+    "changeset": "changeset",
+    "version-packages": "changeset version",
+    "release": "pnpm build && changeset publish",
+    "migrate:tokens": "node scripts/migrate-tokens.mjs",
+    "lint:contrast": "node scripts/lint-contrast.mjs"
+  },
+  "devDependencies": {
+    "@changesets/cli": "^2.27.11",
+    "size-limit": "^11.1.6",
+    "@size-limit/preset-small-lib": "^11.1.6"
+  },
+  "engines": {
+    "node": ">=20",
+    "pnpm": ">=9"
+  },
+  "packageManager": "pnpm@10.33.2"
+}