fix(lint): drop unused Source import after Post.artist_id refactor

backend/app/services/gallery_service.py

@@ -21,7 +21,7 @@ from datetime import datetime
 from sqlalchemy import Select, and_, exists, func, or_, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
-from ..models import Artist, ImageProvenance, ImageRecord, Post, Source, Tag
+from ..models import Artist, ImageProvenance, ImageRecord, Post, Tag
 from ..models.tag import image_tag
 
 CURSOR_SEPARATOR = "|"