fix: 修复全部27个失败的e2e测试

根本原因: 所有测试硬编码了只在生产环境有效的admin token，
CI创建新数据库时token不同导致全部认证失败。

修复:
- CI: 设置已知ADMIN_TOKEN环境变量传给后端和Cypress
- cypress/support/e2e.js: 新增cy.getAdminToken()动态获取token
- 24个spec文件: 硬编码token改为cy.getAdminToken()
- UI选择器: 适配管理页面从tab移到UserMenu、编辑器DOM变化
- API: create_recipe→share_recipe、ingredients格式、权限变化
- 超时: 300s→420s适应32个spec

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/cypress/e2e/audit-log-advanced.cy.js

@@ -1,6 +1,13 @@
 describe('Audit Log Advanced', () => {
-  const ADMIN_TOKEN = 'c86ae7afbe10fabe3c1d5e1a7fee74feaadfd5dc7be2ab62'
-  const authHeaders = { Authorization: `Bearer ${ADMIN_TOKEN}` }
+  let adminToken
+  let authHeaders
+
+  before(() => {
+    cy.getAdminToken().then(token => {
+      adminToken = token
+      authHeaders = { Authorization: `Bearer ${token}` }
+    })
+  })
 
   it('fetches audit logs with pagination', () => {
     cy.request({ url: '/api/audit-log?limit=10&offset=0', headers: authHeaders }).then(res => {
@@ -39,7 +46,7 @@ describe('Audit Log Advanced', () => {
       body: { name: 'Cypress审计测试', note: '', ingredients: [{ oil_name: '薰衣草', drops: 1 }], tags: [] }
     }).then(createRes => {
       const recipeId = createRes.body.id
-      // Check audit log
+      // Check audit log — admin creates recipes with action 'share_recipe'
       cy.request({ url: '/api/audit-log?limit=5&offset=0', headers: authHeaders }).then(res => {
         const entry = res.body.find(e => e.action === 'share_recipe' && e.target_name === 'Cypress审计测试')
         expect(entry).to.exist