feat: 重构前后端架构，添加Go后端和Python Agent服务

- 新增 Go 语言后端服务(server/)，包含用户认证、Agent管理、数据库连接等API
- 新增 Python Agent 服务(agent/)，实现Agent核心逻辑和工具集
- 前端从原生HTML迁移到Vue.js框架(web/src/)
- 添加 Docker Compose 支持(docker-compose.yml)
- 添加项目架构文档(docs/ARCHITECTURE.md)
- 添加环境变量示例(.env.example)和本地启动脚本(start-local.ps1)

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

server/internal/service/approval_service.go

@@ -0,0 +1,101 @@
+package service
+
+import (
+	"fmt"
+	"time"
+
+	"x-agents/server/internal/model"
+	"x-agents/server/internal/repository"
+
+	"github.com/google/uuid"
+)
+
+type ApprovalService struct {
+	auditRepo *repository.AuditRepository
+}
+
+func NewApprovalService(auditRepo *repository.AuditRepository) *ApprovalService {
+	return &ApprovalService{auditRepo: auditRepo}
+}
+
+// CreateApprovalRequest 创建审批请求
+func (s *ApprovalService) CreateApprovalRequest(
+	toolName string,
+	params map[string]interface{},
+	userID string,
+	agentID string,
+	reason string,
+) (*model.ToolApprovalRequest, error) {
+
+	req := &model.ToolApprovalRequest{
+		ID:       uuid.New().String(),
+		ToolName: toolName,
+		Params:   params,
+		UserID:   userID,
+		AgentID:  agentID,
+		Reason:   reason,
+		Status:   model.ApprovalStatusPending,
+	}
+
+	if err := s.auditRepo.CreateApproval(req); err != nil {
+		return nil, err
+	}
+
+	return req, nil
+}
+
+// Approve 批准请求
+func (s *ApprovalService) Approve(requestID, reviewedBy string) (*model.ToolApprovalRequest, error) {
+	req, err := s.auditRepo.FindApprovalByID(requestID)
+	if err != nil {
+		return nil, fmt.Errorf("request not found: %w", err)
+	}
+
+	if req.Status != model.ApprovalStatusPending {
+		return nil, fmt.Errorf("request already processed")
+	}
+
+	now := time.Now()
+	req.Status = model.ApprovalStatusApproved
+	req.ReviewedBy = &reviewedBy
+	req.ReviewedAt = &now
+
+	if err := s.auditRepo.UpdateApproval(req); err != nil {
+		return nil, err
+	}
+
+	return req, nil
+}
+
+// Reject 拒绝请求
+func (s *ApprovalService) Reject(requestID, reviewedBy string) (*model.ToolApprovalRequest, error) {
+	req, err := s.auditRepo.FindApprovalByID(requestID)
+	if err != nil {
+		return nil, fmt.Errorf("request not found: %w", err)
+	}
+
+	if req.Status != model.ApprovalStatusPending {
+		return nil, fmt.Errorf("request already processed")
+	}
+
+	now := time.Now()
+	req.Status = model.ApprovalStatusRejected
+	req.ReviewedBy = &reviewedBy
+	req.ReviewedAt = &now
+
+	if err := s.auditRepo.UpdateApproval(req); err != nil {
+		return nil, err
+	}
+
+	return req, nil
+}
+
+// GetApproval 获取审批状态
+func (s *ApprovalService) GetApproval(requestID string) (*model.ToolApprovalRequest, error) {
+	return s.auditRepo.FindApprovalByID(requestID)
+}
+
+// GetPendingApprovals 获取待审批列表
+func (s *ApprovalService) GetPendingApprovals() ([]model.ToolApprovalRequest, error) {
+	return s.auditRepo.FindPendingApprovals()
+}