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>

agent/app/security/audit.py

@@ -0,0 +1,81 @@
+"""
+审计日志 - 记录所有 Agent 操作
+"""
+import json
+from datetime import datetime
+from typing import Any, Dict, Optional
+from pathlib import Path
+
+
+class AuditLogger:
+    """审计日志记录器"""
+
+    def __init__(self, log_file: str = "audit.log"):
+        self.log_file = log_file
+
+    def log(
+        self,
+        action: str,
+        agent_id: str = "",
+        session_id: str = "",
+        user_id: str = "",
+        details: Dict[str, Any] = None,
+        result: str = "success"
+    ):
+        """记录审计日志"""
+        entry = {
+            "timestamp": datetime.now().isoformat(),
+            "action": action,
+            "agent_id": agent_id,
+            "session_id": session_id,
+            "user_id": user_id,
+            "details": details or {},
+            "result": result
+        }
+
+        # 写入文件
+        self._write_log(entry)
+
+        # TODO: 发送到 Go 后端
+
+    def log_tool_execution(
+        self,
+        tool_name: str,
+        params: Dict[str, Any],
+        user_id: str,
+        agent_id: str,
+        approved: bool,
+        result: Any
+    ):
+        """记录工具执行"""
+        self.log(
+            action="tool_execution",
+            agent_id=agent_id,
+            user_id=user_id,
+            details={
+                "tool_name": tool_name,
+                "params": params,
+                "approved": approved,
+                "result_preview": str(result)[:200] if result else None
+            },
+            result="approved" if approved else "pending_approval"
+        )
+
+    def log_error(self, action: str, error: str, **kwargs):
+        """记录错误"""
+        self.log(
+            action=action,
+            details={"error": error, **kwargs},
+            result="error"
+        )
+
+    def _write_log(self, entry: dict):
+        """写入日志文件"""
+        try:
+            log_path = Path(self.log_file)
+            log_path.parent.mkdir(parents=True, exist_ok=True)
+
+            with open(log_path, "a", encoding="utf-8") as f:
+                f.write(json.dumps(entry, ensure_ascii=False) + "\n")
+        except Exception as e:
+            print(f"Failed to write audit log: {e}")