📋 飞行侠添加：会议纪要生成

新增:
- meetings/utils.py: 纪要生成工具函数
  - generate_meeting_minutes(): 生成纪要数据
  - export_minutes_to_markdown(): 导出 Markdown
- meetings/views.py: minutes action
  - 支持 JSON 和 Markdown 两种格式
  - 自动统计参会者消息数
  - 提取待办事项
- test_minutes.py: 纪要测试脚本

使用:
- GET /api/v1/meetings/{id}/minutes/ → JSON
- GET /api/v1/meetings/{id}/minutes/?output=markdown → Markdown

backend/meetings/views.py

@@ -274,6 +274,28 @@ class MeetingViewSet(viewsets.ModelViewSet):
         )
         
         return Response(MessageSerializer(message).data, status=status.HTTP_201_CREATED)
+    
+    @action(detail=True, methods=['get'], url_path='minutes')
+    def minutes(self, request, pk=None):
+        """生成会议纪要"""
+        meeting = self.get_object()
+        
+        try:
+            from .utils import generate_meeting_minutes, export_minutes_to_markdown
+            
+            minutes = generate_meeting_minutes(str(meeting.id))
+            output_format = request.query_params.get('output', 'json')
+            
+            if output_format == 'markdown':
+                md_content = export_minutes_to_markdown(minutes)
+                return Response({'markdown': md_content})
+            else:
+                return Response(minutes)
+        except Exception as e:
+            return Response(
+                {'error': f'生成纪要失败：{str(e)}'},
+                status=status.HTTP_500_INTERNAL_SERVER_ERROR
+            )
 
 
 class ParticipantViewSet(viewsets.ModelViewSet):