feat(user): 新增用户信息（访问者）返回是否关注is_follow CRUD同步新增exists方法

core/db/crud.py

@@ -152,6 +152,15 @@ class CRUD:
         await self.session.commit()
         return result.rowcount > 0
 
+    async def exists(self, filters: dict, model: Model = None) -> bool:
+        model = model or self.model
+
+        result = await self.session.execute(select(model).filter(
+            *self.build_filter_conditions(filters, model))
+        )
+        state = True if result.scalars().first() else False
+        return state
+
     async def total(self, filters: dict, model: Model = None) -> int:
         model = model or self.model