fix: 修复步骤3抓取网页问题

- 去掉[:5]限制，现在抓取所有互联网搜索结果
- 创建background_tasks记录，在/search页面显示抓取进度
- 每抓取一个URL更新进度和当前项
- 完成/失败/停止时更新任务状态

services/process_monitor.py

@@ -105,12 +105,36 @@ class ProcessMonitor:
                 try:
                     fetched = []
                     failed_count = 0
-                    urls_to_fetch = [r['url'] for r in all_data['internet_results'][:5]]
+                    urls_to_fetch = [r['url'] for r in all_data['internet_results']]
+                    total_urls = len(urls_to_fetch)
+                    
+                    # 创建后台任务记录，这样 /search 页面能看到进度
+                    bg_task_id = f"fetch_{session_id}"
+                    db.create_task(bg_task_id, 'fetch_urls', {
+                        'total': total_urls,
+                        'auto_save': True,
+                        'category': category,
+                        'source': 'process_monitor',
+                        'product_name': product_name
+                    })
+                    db.update_task_status(bg_task_id, 'running', total=total_urls)
                     
                     for i, url in enumerate(urls_to_fetch):
                         if self._check_pause(session_id):
+                            db.update_task_status(bg_task_id, 'stopped', progress=i)
                             break
                         
+                        # 获取当前URL对应的标题
+                        result_item = next((r for r in all_data['internet_results'] if r.get('url') == url), {})
+                        current_title = result_item.get('title', url[:50])
+                        
+                        # 更新后台任务进度
+                        db.update_task_status(
+                            bg_task_id, 'running',
+                            progress=i,
+                            current_item=current_title
+                        )
+                        
                         fetch_result = search_service.fetch_url_content(url)
                         if fetch_result.get('success'):
                             title = fetch_result.get('title', '')
@@ -158,10 +182,25 @@ class ProcessMonitor:
                         
                         time.sleep(0.3)
                     
+                    # 更新后台任务状态为完成
+                    db.update_task_status(
+                        bg_task_id, 'completed',
+                        progress=total_urls,
+                        result={
+                            'total': total_urls,
+                            'success': len(fetched),
+                            'failed': failed_count,
+                            'saved': len(fetched)
+                        }
+                    )
+                    
                     all_data['fetched_contents'] = fetched
                     self._complete_step(session_id, 3, {'count': len(fetched), 'failed': failed_count})
                     logger.info(f"[{session_id}] 步骤3完成: 抓取 {len(fetched)} 个网页, 失败 {failed_count} 个")
                 except Exception as e:
+                    # 更新后台任务状态为失败
+                    if 'bg_task_id' in locals():
+                        db.update_task_status(bg_task_id, 'failed', error_message=str(e))
                     self._fail_step(session_id, 3, str(e))
             
             # 步骤4: 提取产品数据（调用智能体执行）