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/ai/providers/__init__.py

@@ -6,5 +6,6 @@ from .spark import SparkProvider
 from .sensenova import SensenovaProvider
 from .opencode_go import OpencodeGoProvider
 from .nvidia import NvidiaProvider
+from .alibaba import AlibabaMTProvider
 
-__all__ = ["OpenAIProvider", "ClaudeProvider", "DeepLProvider", "LocalProvider", "SparkProvider", "SensenovaProvider", "OpencodeGoProvider", "NvidiaProvider"]
+__all__ = ["OpenAIProvider", "ClaudeProvider", "DeepLProvider", "LocalProvider", "SparkProvider", "SensenovaProvider", "OpencodeGoProvider", "NvidiaProvider", "AlibabaMTProvider"]

backend/app/ai/providers/alibaba.py

@@ -0,0 +1,98 @@
+from typing import Dict, Any, Optional
+from aliyunsdkcore.client import AcsClient
+from aliyunsdkalimt.request.v20181012 import TranslateGeneralRequest, TranslateECommerceRequest
+from app.services.translation_quota import TranslationQuotaService
+from app.database import AsyncSessionLocal
+import asyncio
+import json
+import logging
+
+logger = logging.getLogger(__name__)
+
+ALIBABA_LANG_MAP = {
+    "zh": "zh", "en": "en", "ja": "ja", "ko": "ko",
+    "fr": "fr", "de": "de", "es": "es", "pt": "pt",
+    "ru": "ru", "ar": "ar", "th": "th", "vi": "vi",
+    "id": "id", "ms": "ms", "tl": "tl", "hi": "hi",
+}
+
+
+class AlibabaMTProvider:
+    def __init__(self, access_key_id: str, access_key_secret: str,
+                 region_id: str = "cn-hangzhou"):
+        self.client = AcsClient(access_key_id, access_key_secret, region_id)
+        self._name = "alibaba-mt"
+
+    async def translate(self, text: str, source_lang: Optional[str],
+                        target_lang: str, context: Optional[str] = None) -> Dict[str, Any]:
+        src = source_lang if source_lang and source_lang != "auto" else "auto"
+        tgt = ALIBABA_LANG_MAP.get(target_lang[:2].lower(), "en")
+
+        async with AsyncSessionLocal() as db:
+            quota_svc = TranslationQuotaService(db)
+
+            for version in ("ecommerce", "general"):
+                if not await quota_svc.check_quota(version):
+                    logger.info(f"Quota [{version}] exhausted or disabled, trying next")
+                    continue
+
+                result = await self._do_translate(version, text, src, tgt)
+                if result and result.get("translated_text"):
+                    await quota_svc.consume(version, len(text))
+                    await db.commit()
+                    result["provider"] = f"{self.name}-{version}"
+                    return result
+
+        raise Exception("Alibaba MT: both versions quota exhausted or API failed")
+
+    async def _do_translate(self, version: str, text: str, src: str,
+                            tgt: str) -> Optional[Dict[str, Any]]:
+        try:
+            if version == "ecommerce":
+                req = TranslateECommerceRequest.TranslateECommerceRequest()
+            else:
+                req = TranslateGeneralRequest.TranslateGeneralRequest()
+
+            req.set_FormatType("text")
+            req.set_Scene(version)
+            req.set_SourceLanguage(src)
+            req.set_TargetLanguage(tgt)
+            req.set_SourceText(text)
+
+            loop = asyncio.get_event_loop()
+            body = await loop.run_in_executor(None, self.client.do_action_with_exception, req)
+            resp = json.loads(body)
+            data = resp.get("Data", {})
+            translated = data.get("Translated", "")
+            detected = data.get("DetectedLanguage", src)
+
+            if translated:
+                logger.info(f"Alibaba MT [{version}] ok: {text[:20]}... -> {translated[:20]}...")
+                return {
+                    "translated_text": translated,
+                    "provider": f"{self.name}-{version}",
+                    "detected_source_lang": detected,
+                    "char_count": len(text),
+                    "cost": 0,
+                }
+        except Exception as e:
+            logger.warning(f"Alibaba MT [{version}] failed: {e}")
+
+        return None
+
+    async def reply(self, *args, **kwargs) -> Dict[str, Any]:
+        raise NotImplementedError("Alibaba MT does not support reply generation")
+
+    async def generate_marketing(self, *args, **kwargs) -> Dict[str, Any]:
+        raise NotImplementedError("Alibaba MT does not support marketing generation")
+
+    async def extract_info(self, text: str, schema: Dict[str, Any]) -> Dict[str, Any]:
+        raise NotImplementedError("Alibaba MT does not support info extraction")
+
+    @property
+    def name(self) -> str:
+        return self._name
+
+    @property
+    def cost_per_1k_tokens(self) -> float:
+        return 0

backend/app/ai/router.py

@@ -1,6 +1,6 @@
 from typing import Dict, Any, Optional, List
 from app.ai.base import AIProvider
-from app.ai.providers import OpenAIProvider, ClaudeProvider, DeepLProvider, LocalProvider, SparkProvider, SensenovaProvider, OpencodeGoProvider, NvidiaProvider
+from app.ai.providers import OpenAIProvider, ClaudeProvider, DeepLProvider, LocalProvider, SparkProvider, SensenovaProvider, OpencodeGoProvider, NvidiaProvider, AlibabaMTProvider
 from app.config import settings
 from app.ai.trade_corpus import TradeCorpus
 import logging
@@ -81,6 +81,16 @@ class AIRouter:
             except Exception as e:
                 logger.warning(f"Spark init failed: {e}")
 
+        if settings.ALIBABA_ACCESS_KEY_ID and settings.ALIBABA_ACCESS_KEY_SECRET:
+            try:
+                self.providers["alibaba-mt"] = AlibabaMTProvider(
+                    access_key_id=settings.ALIBABA_ACCESS_KEY_ID,
+                    access_key_secret=settings.ALIBABA_ACCESS_KEY_SECRET,
+                )
+                logger.info("Alibaba MT provider ready")
+            except Exception as e:
+                logger.warning(f"Alibaba MT init failed: {e}")
+
         if settings.LOCAL_MODEL_ENABLED:
             try:
                 self.providers["local"] = LocalProvider(model_url=settings.LOCAL_MODEL_URL)