🔧 修复：扫描龙虾显示正确的名字和 emoji

问题:
- 扫描 API 只返回 agent_id 和 instance_name
- 没有返回 agent_name 和 agent_emoji
- 导致所有龙虾都显示成 🤖

修复:
- 扫描 API 增加 username 参数
- 从 user.linked_agents 获取 agent_name/emoji
- 前端在 username 变化时重新扫描

结果:
✅ flying_hero → 飞行侠 🦸
✅ lobster_monitor → 龙虾监控 🦞

backend/users/views.py

@@ -201,11 +201,24 @@ class ScanLocalAgentsView(views.APIView):
     """
     扫描本机龙虾列表
     
-    GET /api/v1/user/scan-local-agents/?instance_id=xxx - 扫描指定实例
-    GET /api/v1/user/scan-local-agents/ - 扫描所有实例
+    GET /api/v1/user/scan-local-agents/?instance_id=xxx&username=xxx - 扫描指定实例
+    GET /api/v1/user/scan-local-agents/?username=xxx - 扫描所有实例
     """
     def get(self, request):
         instance_id = request.query_params.get('instance_id')
+        username = request.query_params.get('username')
+        
+        # 获取用户绑定的龙虾信息（用于获取 agent_name 和 emoji）
+        user_agents = {}
+        if username:
+            from django.contrib.auth import get_user_model
+            User = get_user_model()
+            try:
+                user = User.objects.get(username=username)
+                for agent in user.linked_agents:
+                    user_agents[agent['agent_id']] = agent
+            except User.DoesNotExist:
+                pass
         
         if not instance_id:
             # 返回所有已注册实例的 Agent
@@ -214,8 +227,11 @@ class ScanLocalAgentsView(views.APIView):
             agents = []
             for inst in instances:
                 for agent_id in inst.agent_ids:
+                    agent_info = user_agents.get(agent_id, {})
                     agents.append({
                         'agent_id': agent_id,
+                        'agent_name': agent_info.get('agent_name', agent_id),
+                        'agent_emoji': agent_info.get('agent_emoji', '🤖'),
                         'instance_id': inst.instance_id,
                         'instance_name': inst.instance_name
                     })
@@ -224,11 +240,15 @@ class ScanLocalAgentsView(views.APIView):
             from instances.models import Instance
             try:
                 instance = Instance.objects.get(instance_id=instance_id, is_active=True)
-                agents = [{
-                    'agent_id': agent_id,
-                    'instance_id': instance.instance_id,
-                    'instance_name': instance.instance_name
-                } for agent_id in instance.agent_ids]
+                for agent_id in instance.agent_ids:
+                    agent_info = user_agents.get(agent_id, {})
+                    agents.append({
+                        'agent_id': agent_id,
+                        'agent_name': agent_info.get('agent_name', agent_id),
+                        'agent_emoji': agent_info.get('agent_emoji', '🤖'),
+                        'instance_id': instance.instance_id,
+                        'instance_name': instance.instance_name
+                    })
             except Instance.DoesNotExist:
                 return Response({'error': '实例不存在'}, status=status.HTTP_404_NOT_FOUND)