```

feat(ai_agent): 完善AI适配器和服务功能

- 添加OpenClaw和Hermes健康检查接口
- 实现OpenClaw工具调用功能
- 重构AI适配器使用常量定义
- 增加AI技能系统支持
- 更新配置文件中的默认模型提供者设置

refactor(scheduler): 使用常量替换硬编码值

- 将硬编码的actor值替换为ActorValue常量
- 将receive_id_type替换为FeishuReceiveIdType枚举

refactor(audit): 统一审计日志常量使用

- 将硬编码的actor、source、risk_level等值替换为对应常量
- 更新审核服务中的状态和操作常量引用

refactor(approvals): 标准化审批模块常量使用

- 将applicant默认值替换为ActorValue.API常量
- 使用ApprovalStatus常量替代硬编码状态值
- 更新审核操作常量引用
```

app/modules/approvals/service.py

@@ -5,8 +5,10 @@ from fastapi import HTTPException, status
 from sqlalchemy import select
 from sqlalchemy.orm import Session
 
+from app.modules.approvals.constants import ApprovalActionValue, ApprovalStatus
 from app.modules.approvals.models import ApprovalRequest
 from app.modules.approvals.schemas import ApprovalCreate
+from app.modules.audit.constants import AuditAction, AuditRiskLevel, AuditSource
 from app.modules.audit.schemas import AuditLogCreate
 from app.modules.audit.service import AuditService
 
@@ -34,11 +36,11 @@ class ApprovalService:
         self.audit.log(
             AuditLogCreate(
                 actor=payload.applicant,
-                source="approval",
-                action="approval.create",
+                source=AuditSource.APPROVAL,
+                action=AuditAction.APPROVAL_CREATE,
                 target_type=payload.domain,
                 target_id=payload.record_id,
-                risk_level="medium",
+                risk_level=AuditRiskLevel.MEDIUM,
                 request_payload=payload.model_dump(),
                 response_payload={"ticket_id": ticket.ticket_id, "status": ticket.status},
             )
@@ -70,9 +72,9 @@ class ApprovalService:
         comment: str | None,
     ) -> ApprovalRequest:
         ticket = self.get_by_ticket(ticket_id)
-        if ticket.status != "pending":
+        if ticket.status != ApprovalStatus.PENDING:
             raise HTTPException(status_code=409, detail="Approval ticket already decided")
-        ticket.status = "approved" if approved else "rejected"
+        ticket.status = ApprovalStatus.APPROVED if approved else ApprovalStatus.REJECTED
         ticket.approver = approver
         ticket.decision_comment = comment
         from datetime import datetime
@@ -83,11 +85,11 @@ class ApprovalService:
         self.audit.log(
             AuditLogCreate(
                 actor=approver,
-                source="approval",
-                action="approval.approve" if approved else "approval.reject",
+                source=AuditSource.APPROVAL,
+                action=AuditAction.APPROVAL_APPROVE if approved else AuditAction.APPROVAL_REJECT,
                 target_type=ticket.domain,
                 target_id=ticket.record_id,
-                risk_level="high",
+                risk_level=AuditRiskLevel.HIGH,
                 request_payload={"ticket_id": ticket_id, "comment": comment},
                 response_payload={"status": ticket.status},
             )
@@ -102,10 +104,15 @@ class ApprovalService:
         action: str,
     ) -> bool:
         ticket = self.get_by_ticket(ticket_id)
-        if ticket.status != "approved":
+        if ticket.status != ApprovalStatus.APPROVED:
             return False
         if ticket.domain != domain:
             return False
         if ticket.record_id and record_id is not None and str(ticket.record_id) != str(record_id):
             return False
-        return ticket.action in {action, "update", f"update:{domain}", "*"}
+        return ticket.action in {
+            action,
+            ApprovalActionValue.UPDATE,
+            f"{ApprovalActionValue.UPDATE}:{domain}",
+            ApprovalActionValue.WILDCARD,
+        }