baseline: 批次A-D 成果 + membership 半成品（测试红）

backend/apps/core/serializers.py

@@ -0,0 +1,20 @@
+"""核心应用公共组件：async 序列化器基类（adrf 0.1.14+ 需要 asave/acreate）。"""
+
+from rest_framework import serializers as drf_serializers
+from asgiref.sync import sync_to_async
+
+
+class AsyncModelSerializer(drf_serializers.ModelSerializer):
+    """给所有需要的 model serializer 加 asave / acreate。"""
+
+    async def asave(self, **kwargs):
+        return await sync_to_async(self.save)(**kwargs)
+
+    async def acreate(self, validated_data):
+        return await sync_to_async(self.Meta.model.objects.create)(**validated_data)
+
+
+# 兼容旧路径：apps.core.views.AsyncModelSerializer
+from apps.core import views as _views  # noqa: E402
+if not hasattr(_views, "AsyncModelSerializer"):
+    _views.AsyncModelSerializer = AsyncModelSerializer