fix: 修复剩余6个e2e失败 — 选择器/路由/超时/默认tab

- manage-recipes: 展开公共配方库section后再查找recipe-row
- pr27-features: /#/manage改为/manage（HTML5 history模式）
- performance: 搜索后接受empty-hint作为有效结果
- recipe-search: .empty-state改为.empty-hint
- demo-walkthrough: 超时从15s加到20s
- diary-flow: 默认tab是brand不是diary，改为验证brand内容

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

frontend/cypress/e2e/diary-flow.cy.js

@@ -185,15 +185,16 @@ describe('Diary Flow', () => {
       cy.contains('我的账户').should('be.visible')
     })
 
-    it('diary grid is visible on diary tab', () => {
+    it('brand tab content is visible by default', () => {
       cy.visit('/mydiary', {
         onBeforeLoad(win) {
           win.localStorage.setItem('oil_auth_token', adminToken)
         }
       })
       cy.get('.my-diary', { timeout: 10000 }).should('exist')
-      // Diary grid or empty hint should be present
-      cy.get('.diary-grid, .empty-hint').should('exist')
+      // Default tab is brand; section card with upload areas should be present
+      cy.get('.section-card, .sub-tab.active', { timeout: 10000 }).should('exist')
+      cy.get('.sub-tab.active').should('contain', '我的品牌')
     })
   })