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

backend/apps/report/serializers.py

@@ -0,0 +1,16 @@
+from rest_framework import serializers
+from apps.core.serializers import AsyncModelSerializer
+from .models import ReportDefinition
+
+
+class ReportDefinitionSerializer(AsyncModelSerializer):
+    category_name = serializers.CharField(source="get_category_display", read_only=True)
+
+    class Meta:
+        model = ReportDefinition
+        fields = [
+            "id", "code", "name", "category", "category_name",
+            "description", "is_system", "is_active", "query_config",
+            "created_at", "updated_at",
+        ]
+        read_only_fields = ["id", "is_system", "created_at", "updated_at"]