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/handler/approval_handler.go

@@ -0,0 +1,80 @@
+package handler
+
+import (
+	"net/http"
+
+	"x-agents/server/internal/model"
+	"x-agents/server/internal/service"
+
+	"github.com/gin-gonic/gin"
+)
+
+type ApprovalHandler struct {
+	approvalService *service.ApprovalService
+}
+
+func NewApprovalHandler(approvalService *service.ApprovalService) *ApprovalHandler {
+	return &ApprovalHandler{approvalService: approvalService}
+}
+
+// Approve 处理审批请求
+func (h *ApprovalHandler) Approve(c *gin.Context) {
+	var req struct {
+		RequestID string `json:"request_id" binding:"required"`
+		Approved  bool   `json:"approved"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	userID, exists := c.Get("user_id")
+	if !exists {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "unauthorized"})
+		return
+	}
+
+	var result interface{}
+	var err error
+
+	if req.Approved {
+		result, err = h.approvalService.Approve(req.RequestID, userID.(string))
+	} else {
+		result, err = h.approvalService.Reject(req.RequestID, userID.(string))
+	}
+
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, result)
+}
+
+// GetStatus 获取审批状态
+func (h *ApprovalHandler) GetStatus(c *gin.Context) {
+	requestID := c.Param("id")
+
+	result, err := h.approvalService.GetApproval(requestID)
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "request not found"})
+		return
+	}
+
+	c.JSON(http.StatusOK, result)
+}
+
+// ListPending 获取待审批列表
+func (h *ApprovalHandler) ListPending(c *gin.Context) {
+	result, err := h.approvalService.GetPendingApprovals()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	if result == nil {
+		result = []model.ToolApprovalRequest{}
+	}
+
+	c.JSON(http.StatusOK, gin.H{"pending": result})
+}