Add library build for package distribution

Add a separate Vite library build (vite.lib.config.ts + `build:lib`) that
bundles src/index.ts to ESM with React/react-dom externalised and the 97
internal `@/` imports resolved at build time, plus type declarations and
copies of tokens.css / typography.css into dist. Point package.json
exports/main/types at dist and make react a peer dependency, so ADS can be
consumed as an installed package (@geljic/ads3-design-system) rather than a
file: + `@/` alias dependency.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

package.json

@@ -3,15 +3,24 @@
   "private": true,
   "version": "0.1.0",
   "type": "module",
-  "main": "./src/index.ts",
+  "main": "./dist/index.js",
+  "module": "./dist/index.js",
+  "types": "./dist/src/index.d.ts",
+  "files": [
+    "dist"
+  ],
   "exports": {
-    ".": "./src/index.ts",
-    "./tokens": "./src/tokens/tokens.css",
-    "./utils": "./src/lib/utils.ts"
+    ".": {
+      "types": "./dist/src/index.d.ts",
+      "import": "./dist/index.js"
+    },
+    "./tokens": "./dist/tokens.css",
+    "./typography": "./dist/typography.css"
   },
   "scripts": {
     "dev": "vite",
     "build": "tsc -b && vite build",
+    "build:lib": "vite build --config vite.lib.config.ts && cp src/tokens/tokens.css src/styles/typography.css dist/",
     "lint": "eslint .",
     "preview": "vite preview",
     "storybook": "storybook dev -p 6006",
@@ -26,14 +35,13 @@
     "@fontsource-variable/public-sans": "^5.2.7",
     "@tailwindcss/vite": "^4.3.0",
     "clsx": "^2.1.1",
-    "react": "^19.2.6",
-    "react-dom": "^19.2.6",
     "tailwind-merge": "^3.6.0",
     "tailwindcss": "^4.3.0"
   },
   "devDependencies": {
     "@chromatic-com/storybook": "^5.2.1",
     "@eslint/js": "^10.0.1",
+    "@microsoft/api-extractor": "^7.58.7",
     "@storybook/addon-a11y": "^10.4.0",
     "@storybook/addon-designs": "^11.1.3",
     "@storybook/addon-docs": "^10.4.0",
@@ -60,6 +68,7 @@
     "typescript": "~6.0.2",
     "typescript-eslint": "^8.59.2",
     "vite": "^8.0.12",
+    "vite-plugin-dts": "^5.0.2",
     "vitest": "^4.1.6"
   }
 }