chore: post-deployment cleanup and docs update

- Make AI routing rules DB-driven (read from system_configs, removed from config.py)
- Add translation quota tracking to LLM translation (OpenAIProvider)
- Add Alibaba MT ECS RAM role support (STS token, no AccessKey needed)
- Fix admin sidebar link for AI模型配置 page
- Fix Quota.vue API path (quotas → translation-quotas)
- Fix login auto-redirect to dashboard
- Add provider dropdown selects to AI routing config UI
- Clean up stale ai_provider_* system_configs records
- Remove OpencodeGo, Spark providers (code + DB)
- Update deploy config: nginx port 8000, systemd cwd

backend/app/config.py

@@ -32,13 +32,7 @@ class Settings(BaseSettings):
     SENSENOVA_BASE_URL: str = "https://token.sensenova.cn/v1"
     SENSENOVA_MODEL: str = "deepseek-v4-flash"
 
-    IFLYTEK_API_KEY: Optional[str] = None
-    IFLYTEK_API_BASE: str = "https://maas-api.cn-huabei-1.xf-yun.com/v2"
-    IFLYTEK_MODEL: str = "astron-code-latest"
 
-    OPENCODE_GO_API_KEY: Optional[str] = None
-    OPENCODE_GO_BASE_URL: str = "https://opencode.ai/zen/go/v1"
-    OPENCODE_GO_MODEL: str = "minimax-m2.7"
 
     NVIDIA_API_KEY: Optional[str] = None
     NVIDIA_BASE_URL: str = "https://integrate.api.nvidia.com/v1"
@@ -74,15 +68,6 @@ class Settings(BaseSettings):
     SENTRY_DSN: Optional[str] = None
     DEBUG: bool = True
 
-    AI_ROUTING: dict = {
-        "translate": {"primary": "sensenova", "fallback": ["alibaba-mt", "opencode_go"]},
-        "reply": {"primary": "sensenova", "fallback": ["opencode_go"]},
-        "marketing": {"primary": "sensenova", "fallback": ["opencode_go"]},
-        "extract": {"primary": "sensenova", "fallback": ["opencode_go"]},
-        "quotation": {"primary": "sensenova", "fallback": ["opencode_go"]},
-        "chat": {"primary": "sensenova", "fallback": ["opencode_go", "nvidia"]},
-    }
-
     FREE_DAILY_TRANSLATE_CHARS: int = 5000
     FREE_DAILY_REPLIES: int = 20
     FREE_DAILY_MARKETING: int = 5