test(web): add Vitest smoke test and jsdom config

web/src/lib/example.test.ts

@@ -0,0 +1,7 @@
+import { describe, expect, it } from 'vitest';
+
+describe('scaffold smoke', () => {
+  it('runs vitest', () => {
+    expect(1 + 1).toBe(2);
+  });
+});

web/vitest.config.ts

@@ -0,0 +1,10 @@
+import { sveltekit } from '@sveltejs/kit/vite';
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  plugins: [sveltekit()],
+  test: {
+    environment: 'jsdom',
+    include: ['src/**/*.test.ts']
+  }
+});