细节优化

backend/app/core/config.py

@@ -38,6 +38,10 @@ class Settings(BaseSettings):
     rate_limit_per_token_per_min: int = 60
     rate_limit_per_ip_per_min: int = 30
 
+    # --- 数据保留 ---
+    # 访问日志保留天数，超过自动清理（0 = 永久保留，不推荐）
+    access_log_retention_days: int = 90
+
     # --- CORS ---
     frontend_origin: str = "http://localhost:5173"
 

backend/app/core/errors.py

@@ -83,6 +83,13 @@ class RateLimitedError(AppError):
     message = "请求过于频繁，请稍后再试。"
 
 
+class LinkExpiredError(AppError):
+    """AI 链接已过期（HTTP 410 Gone）。"""
+    status_code = status.HTTP_410_GONE
+    code = "LINK_EXPIRED"
+    message = "链接已失效，请重新生成。"
+
+
 # --- 上传与配额 ---