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

backend/app/config.py

@@ -55,10 +55,20 @@ class Settings(BaseSettings):
     WHATSAPP_PHONE_NUMBER_ID: Optional[str] = None
     WHATSAPP_WEBHOOK_VERIFY_TOKEN: Optional[str] = None
 
+    ALIBABA_ACCESS_KEY_ID: Optional[str] = None
+    ALIBABA_ACCESS_KEY_SECRET: Optional[str] = None
+
     WECHAT_APP_ID: Optional[str] = None
     WECHAT_APP_SECRET: Optional[str] = None
     WECHAT_PUSH_TEMPLATE_ID: Optional[str] = None
 
+    WECHAT_PAY_MCH_ID: Optional[str] = None
+    WECHAT_PAY_API_KEY: Optional[str] = None
+    WECHAT_PAY_SERIAL_NO: Optional[str] = None
+    WECHAT_PAY_CERT_DIR: str = "./certs"
+    WECHAT_PAY_NOTIFY_URL: str = "https://example.com/api/v1/payment/notify"
+    WECHAT_PAY_API_BASE: str = "https://api.mch.weixin.qq.com"
+
     EXCHANGE_RATE_API_KEY: Optional[str] = None
 
     UPLOAD_DIR: str = "./uploads"
@@ -71,7 +81,7 @@ class Settings(BaseSettings):
     DEBUG: bool = True
 
     AI_ROUTING: dict = {
-        "translate": {"primary": "opencode_go", "fallback": ["sensenova", "openai", "local"]},
+        "translate": {"primary": "alibaba-mt", "fallback": ["opencode_go", "sensenova", "openai", "local"]},
         "reply": {"primary": "opencode_go", "fallback": ["sensenova", "anthropic", "local"]},
         "marketing": {"primary": "opencode_go", "fallback": ["sensenova", "openai", "local"]},
         "extract": {"primary": "opencode_go", "fallback": ["sensenova", "openai"]},