Add library build pipeline and token alignment report

- Configure Vite library mode to export MUI theme as plain JS
- Add tsconfig.build.json for declaration generation
- Add package.json exports for theme, Tailwind config, and tokens
- Create src/index.ts as library entry point
- Document token alignment between design system and production
  including colour mapping, flagged conflicts, and breakpoint alignment

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vite.config.ts

@@ -12,4 +12,32 @@ export default defineConfig({
       '@theme': path.resolve(__dirname, 'src/theme'),
     },
   },
+  build: {
+    lib: {
+      entry: path.resolve(__dirname, 'src/index.ts'),
+      formats: ['es'],
+      fileName: 'index',
+    },
+    rollupOptions: {
+      external: [
+        'react',
+        'react-dom',
+        'react/jsx-runtime',
+        '@mui/material',
+        '@mui/material/styles',
+        '@mui/system',
+        '@mui/icons-material',
+        '@emotion/react',
+        '@emotion/styled',
+      ],
+      output: {
+        globals: {
+          react: 'React',
+          'react-dom': 'ReactDOM',
+        },
+      },
+    },
+    outDir: 'dist',
+    sourcemap: true,
+  },
 });