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>

packages/css/package.json

@@ -0,0 +1,43 @@
+{
+  "name": "@managemate/css",
+  "version": "0.1.0",
+  "description": "DSMMG vanilla CSS — tokens, base, components, utilities",
+  "license": "UNLICENSED",
+  "private": true,
+  "sideEffects": [
+    "*.css"
+  ],
+  "main": "./dist/index.css",
+  "style": "./dist/index.css",
+  "exports": {
+    ".": {
+      "style": "./dist/index.css",
+      "default": "./dist/index.css"
+    },
+    "./tokens": "./dist/tokens.css",
+    "./base": "./dist/base.css",
+    "./utilities": "./dist/utilities.css",
+    "./src/*": "./src/*",
+    "./package.json": "./package.json"
+  },
+  "files": [
+    "dist",
+    "src"
+  ],
+  "scripts": {
+    "build": "pnpm run build:bundle && pnpm run build:tokens && pnpm run build:base && pnpm run build:utilities",
+    "build:bundle": "postcss src/index.css --output dist/index.css",
+    "build:tokens": "postcss src/tokens.css --output dist/tokens.css",
+    "build:base": "postcss src/base.css --output dist/base.css",
+    "build:utilities": "postcss src/utilities.css --output dist/utilities.css",
+    "build:min": "cross-env NODE_ENV=production pnpm run build"
+  },
+  "devDependencies": {
+    "autoprefixer": "^10.4.20",
+    "cross-env": "^7.0.3",
+    "cssnano": "^7.0.7",
+    "postcss": "^8.5.0",
+    "postcss-cli": "^11.0.0",
+    "postcss-import": "^16.1.0"
+  }
+}