WP-01: domain contract and failing tests for auth and user management

Domain entities/ports, service stubs, 18 application unit tests with in-memory
fakes, API integration tests for /api/auth and /api/users, Vitest specs for the
auth store, login page and user form, Playwright auth/user-management flow.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

frontend/src/components/UserForm.test.ts

@@ -0,0 +1,42 @@
+import { mount } from '@vue/test-utils'
+import UserForm from './UserForm.vue'
+
+describe('UserForm', () => {
+  it('emits the new user payload in create mode', async () => {
+    const w = mount(UserForm, { props: { mode: 'create' } })
+    await w.find('input[name=email]').setValue('u@x.de')
+    await w.find('input[name=display_name]').setValue('User')
+    await w.find('input[name=password]').setValue('user-password-123')
+    await w.find('select[name=role]').setValue('admin')
+    await w.find('form').trigger('submit')
+    expect(w.emitted('submit')![0][0]).toEqual({
+      email: 'u@x.de',
+      display_name: 'User',
+      password: 'user-password-123',
+      role: 'admin',
+    })
+  })
+
+  it('rejects short passwords client-side', async () => {
+    const w = mount(UserForm, { props: { mode: 'create' } })
+    await w.find('input[name=email]').setValue('u@x.de')
+    await w.find('input[name=display_name]').setValue('User')
+    await w.find('input[name=password]').setValue('short')
+    await w.find('form').trigger('submit')
+    expect(w.emitted('submit')).toBeUndefined()
+    expect(w.text()).toContain('at least 12 characters')
+  })
+
+  it('hides email and password in edit mode and prefills values', () => {
+    const w = mount(UserForm, {
+      props: {
+        mode: 'edit',
+        user: { id: '1', email: 'u@x.de', display_name: 'User', role: 'user', is_active: false },
+      },
+    })
+    expect(w.find('input[name=email]').exists()).toBe(false)
+    expect(w.find('input[name=password]').exists()).toBe(false)
+    expect((w.find('input[name=display_name]').element as HTMLInputElement).value).toBe('User')
+    expect((w.find('input[name=is_active]').element as HTMLInputElement).checked).toBe(false)
+  })
+})