Enhance testing framework and add UI component tests. Integrated Vitest for testing with AstroContainer API. Updated package.json and bun.lock to include testing dependencies. Added comprehensive test cases for various UI components including Button, Alert, Badge, and more, ensuring proper rendering and functionality.

vitest.config.ts

@@ -0,0 +1,7 @@
+import { getViteConfig } from 'astro/config';
+
+export default getViteConfig({
+  test: {
+    environment: 'node'
+  }
+});