chore: add workspace vitest configuration for testing with jsdom and coverage

vitest.config.ts

@@ -0,0 +1,19 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    workspace: [
+      { 
+        extends: true, 
+        test: { 
+          environment: 'jsdom', 
+        }, 
+      }, 
+    ],
+    coverage: {
+      provider: 'v8',
+      include: ['packages/*'],
+      exclude: ['**/node_modules/**', '**/dist/**'],
+    },
+  },
+});