fix: dashboard.py 顶层 import CoverSettings，解决运行时 500

backend/app/api/dashboard.py

@@ -12,11 +12,12 @@ from datetime import datetime
 from pathlib import Path
 
 from fastapi import APIRouter, Depends, HTTPException, UploadFile, File, Form, status
-from sqlmodel import Session
+from sqlmodel import Session, select
 
 from app.core.deps import get_current_user, require_role
 from app.db.session import get_session
 from app.models.user import User, UserRole
+from app.models.cover_settings import CoverSettings
 
 router = APIRouter(prefix="/api/dashboard", tags=["仪表盘"])
 
@@ -41,8 +42,6 @@ def get_current_cover(
     current_user: User = Depends(get_current_user),
 ):
     """查询当前题图设置（三角色均可读）。"""
-    from app.models.cover_settings import CoverSettings
-    
     row = session.exec(
         select(CoverSettings).where(CoverSettings.key == "dashboard_cover")
     ).first()
@@ -95,9 +94,6 @@ def upload_cover(
     with open(filepath, "wb") as f:
         f.write(contents)
 
-    # 更新数据库
-    from app.models.cover_settings import CoverSettings
-    
     cover_path = f"{STATIC_COVERS_URL}/{filename}"
     now = datetime.now()