feat: add Vite library build config with dts generation

Separate vite.lib.config.ts for library mode builds:
- ES module output (index.es.js) with react/react-dom externalized
- Consolidated type declarations via rollupTypes (index.es.d.ts)
- CSS Modules with debuggable scoped names (cameleer_ prefix)
- Deterministic output filenames (style.css, index.es.js)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tsconfig.node.json

@@ -20,5 +20,5 @@
     "noFallthroughCasesInSwitch": true,
     "noUncheckedSideEffectImports": true
   },
-  "include": ["vite.config.ts"]
+  "include": ["vite.config.ts", "vite.lib.config.ts"]
 }

vite.lib.config.ts

@@ -0,0 +1,34 @@
+import { defineConfig } from 'vite'
+import react from '@vitejs/plugin-react'
+import dts from 'vite-plugin-dts'
+import { resolve } from 'path'
+
+export default defineConfig({
+  plugins: [
+    react(),
+    dts({
+      include: ['src/design-system'],
+      exclude: ['**/*.test.tsx', '**/*.test.ts'],
+      outDir: 'dist',
+      tsconfigPath: resolve(__dirname, 'tsconfig.app.json'),
+      rollupTypes: true,
+    }),
+  ],
+  css: {
+    modules: {
+      localsConvention: 'camelCase',
+      generateScopedName: 'cameleer_[name]_[local]_[hash:5]',
+    },
+  },
+  build: {
+    lib: {
+      entry: resolve(__dirname, 'src/design-system/index.ts'),
+      formats: ['es'],
+      fileName: () => 'index.es.js',
+      cssFileName: 'style',
+    },
+    rollupOptions: {
+      external: ['react', 'react-dom', 'react-router-dom', 'react/jsx-runtime'],
+    },
+  },
+})