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/model/audit.go

@@ -0,0 +1,76 @@
+package model
+
+import (
+	"encoding/json"
+	"time"
+)
+
+// AuditAction 审计动作
+type AuditAction string
+
+const (
+	AuditActionLogin         AuditAction = "login"
+	AuditActionLogout        AuditAction = "logout"
+	AuditActionChat          AuditAction = "chat"
+	AuditActionToolExecute   AuditAction = "tool_execute"
+	AuditActionToolApprove   AuditAction = "tool_approve"
+	AuditActionToolReject    AuditAction = "tool_reject"
+	AuditActionAgentCreate   AuditAction = "agent_create"
+	AuditActionAgentUpdate   AuditAction = "agent_update"
+	AuditActionAgentDelete   AuditAction = "agent_delete"
+)
+
+// AuditLog 审计日志
+type AuditLog struct {
+	ID         string      `json:"id" gorm:"primaryKey"`
+	UserID     string      `json:"user_id" gorm:"size:50;index"`
+	AgentID    string      `json:"agent_id" gorm:"size:50;index"`
+	Action     AuditAction `json:"action" gorm:"size:50;index"`
+	Details    JSONMap     `json:"details" gorm:"type:jsonb"`
+	Result     string      `json:"result" gorm:"size:20"` // success, failed, rejected
+	IPAddress  string      `json:"ip_address" gorm:"size:45"`
+	UserAgent  string      `json:"user_agent" gorm:"size:255"`
+	CreatedAt  time.Time   `json:"created_at" gorm:"index"`
+}
+
+// ApprovalStatus 审批状态
+type ApprovalStatus string
+
+const (
+	ApprovalStatusPending   ApprovalStatus = "pending"
+	ApprovalStatusApproved ApprovalStatus = "approved"
+	ApprovalStatusRejected ApprovalStatus = "rejected"
+)
+
+// ToolApprovalRequest 工具审批请求
+type ToolApprovalRequest struct {
+	ID          string          `json:"id" gorm:"primaryKey"`
+	ToolName    string          `json:"tool_name" gorm:"size:100;index"`
+	Params      JSONMap         `json:"params" gorm:"type:jsonb"`
+	UserID      string          `json:"user_id" gorm:"size:50;index"`
+	AgentID     string          `json:"agent_id" gorm:"size:50"`
+	Reason      string          `json:"reason" gorm:"type:text"`
+	Status      ApprovalStatus `json:"status" gorm:"size:20;default:'pending';index"`
+	ReviewedBy  *string         `json:"reviewed_by" gorm:"size:50"`
+	ReviewedAt  *time.Time     `json:"reviewed_at"`
+	Result      *string        `json:"result" gorm:"type:text"` // 执行结果
+	CreatedAt   time.Time      `json:"created_at" gorm:"index"`
+	UpdatedAt   time.Time      `json:"updated_at"`
+}
+
+// JSONMap JSON数据映射
+type JSONMap map[string]interface{}
+
+func (j JSONMap) MarshalJSON() ([]byte, error) {
+	if j == nil {
+		return []byte("null"), nil
+	}
+	return json.Marshal(j)
+}
+
+func (j *JSONMap) UnmarshalJSON(data []byte) error {
+	if j == nil {
+		*j = make(map[string]interface{})
+	}
+	return json.Unmarshal(data, j)
+}