feat: 更新后端agent和skill服务

- agent_handler.go: 新增ListAgents、CreateAgent接口
- skill_handler.go: 更新skill内容获取和保存功能
- agent_service.go: 新增agent服务逻辑
- main.go: 新增agent路由

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/internal/service/agent_service.go

@@ -279,3 +279,118 @@ func (s *AgentService) ChatStream(c interface{}, agentID int, message, sessionID
 
 	return nil
 }
+
+// CreateAgentRequest 创建智能体请求
+type CreateAgentRequest struct {
+	Name         string   `json:"name"`
+	Description  string   `json:"description"`
+	Avatar       string   `json:"avatar"`
+	SkillsMode   string   `json:"skills_mode"`
+	Skills       []string `json:"skills"`
+	Knowledge    string   `json:"knowledge"`
+	Prompt       string   `json:"prompt"`
+	ModelProvider string  `json:"model_provider"`
+	ModelName    string   `json:"model_name"`
+	UserID       int      `json:"user_id"`
+}
+
+// CreateAgentResponse 创建智能体响应
+type CreateAgentResponse struct {
+	AgentID int    `json:"agent_id"`
+	Name    string `json:"name"`
+	Message string `json:"message"`
+}
+
+// CreateAgent 创建智能体
+func (s *AgentService) CreateAgent(req CreateAgentRequest, userID int) (*CreateAgentResponse, error) {
+	url := fmt.Sprintf("%s/agent/create", s.pythonURL)
+
+	// 构建请求体
+	pythonReq := CreateAgentRequest{
+		Name:         req.Name,
+		Description:  req.Description,
+		Avatar:       req.Avatar,
+		SkillsMode:   req.SkillsMode,
+		Skills:       req.Skills,
+		Knowledge:    req.Knowledge,
+		Prompt:       req.Prompt,
+		ModelProvider: req.ModelProvider,
+		ModelName:    req.ModelName,
+		UserID:       userID,
+	}
+
+	jsonData, err := json.Marshal(pythonReq)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal request: %w", err)
+	}
+
+	httpReq, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+	httpReq.Header.Set("Content-Type", "application/json")
+
+	resp, err := s.client.Do(httpReq)
+	if err != nil {
+		return nil, fmt.Errorf("failed to call python agent: %w", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read response: %w", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("python agent error: %s", string(body))
+	}
+
+	var result CreateAgentResponse
+	if err := json.Unmarshal(body, &result); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal response: %w", err)
+	}
+
+	log.Printf("[AgentService] Agent created: %s (ID: %d)", result.Name, result.AgentID)
+
+	return &result, nil
+}
+
+// ListAgentsResponse 获取智能体列表响应
+type ListAgentsResponse struct {
+	Agents []interface{} `json:"agents"`
+}
+
+// ListAgents 获取智能体列表
+func (s *AgentService) ListAgents() (*ListAgentsResponse, error) {
+	url := fmt.Sprintf("%s/agent/list", s.pythonURL)
+
+	httpReq, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+	httpReq.Header.Set("Content-Type", "application/json")
+
+	resp, err := s.client.Do(httpReq)
+	if err != nil {
+		return nil, fmt.Errorf("failed to call python agent: %w", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read response: %w", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("python agent error: %s", string(body))
+	}
+
+	var result ListAgentsResponse
+	if err := json.Unmarshal(body, &result); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal response: %w", err)
+	}
+
+	log.Printf("[AgentService] Listed agents: %d", len(result.Agents))
+
+	return &result, nil
+}