添加异步数据库支持，更新相关模型和会话管理

app/db/models/siteicon.py

@@ -1,7 +1,8 @@
-from sqlalchemy import Column, Integer, String, Sequence
+from sqlalchemy import Column, Integer, String, Sequence, select
+from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import Session
 
-from app.db import db_query, Base
+from app.db import db_query, Base, async_db_query
 
 
 class SiteIcon(Base):
@@ -22,3 +23,9 @@ class SiteIcon(Base):
     @db_query
     def get_by_domain(db: Session, domain: str):
         return db.query(SiteIcon).filter(SiteIcon.domain == domain).first()
+
+    @classmethod
+    @async_db_query
+    async def async_get_by_domain(cls, db: AsyncSession, domain: str):
+        result = await db.execute(select(cls).where(cls.domain == domain))
+        return result.scalar_one_or_none()