feat: WeChat Pay integration, translation quota management, login UX fixes

- WeChat Pay APIv3 integration (JSAPI + Native) with cert-based auth
- TranslationQuota model + admin management UI (配额 tab)
- Alibaba MT provider now checks quota before translation
- Fix: admin tabs scrollable on mobile, remove header-card
- Fix: profile/login navigation - logout stays on profile, login returns to profile
- Fix: login form now visible by default (no extra click to show)
- Fix: home page translate link uses navigateTo (was switchTab to non-tabBar page)
- Add .coverage and apiclient_key.pem to gitignore

uni-app/src/pages/index/index.vue

@@ -427,7 +427,7 @@ const loadData = async () => {
   }
 }
 
-const tabbarPages = [PAGES.INDEX, PAGES.TRANSLATE, PAGES.CUSTOMERS, PAGES.MARKETING, PAGES.QUOTATION]
+const tabbarPages = [PAGES.INDEX, PAGES.CUSTOMERS, PAGES.MARKETING, PAGES.QUOTATION]
 
 const goToPage = (url) => {
   if (tabbarPages.includes(url)) {
@@ -443,7 +443,7 @@ const goToLogin = () => {
         content: '请先登录',
         success: (res) => {
           if (res.confirm) {
-            uni.reLaunch({ url: PAGES.LOGIN })
+            uni.navigateTo({ url: PAGES.LOGIN })
       }
     },
   })