feat: add frontend

frontend/test/Header.spec.js

@@ -0,0 +1,13 @@
+import { mount } from '@vue/test-utils'
+import Header from '@/components/Header.vue'
+
+describe('Header', () => {
+  test('is a Vue instance', () => {
+    const wrapper = mount(Header, {
+      stubs: {
+        NuxtLink: true,
+      },
+    });
+    expect(wrapper.vm).toBeTruthy()
+  })
+})