```

refactor: 移除审批和回写功能模块

移除了整个审批(approvals)和官方回写(writebacks)功能模块，
包括相关模型、路由、服务和配置项。更新了数据库迁移文件，
删除了相关的审批请求表和官方回写运行表。同时从API路由器中
移除了相应的路由，并调整了安全常量和字段验证器以匹配变更。
```

app/modules/feishu/constants.py

@@ -98,18 +98,6 @@ class FeishuEventReceiptKey(StrEnum):
     MESSAGE_ID = "message_id"
 
 
-class FeishuApprovalAction(StrEnum):
-    APPROVE = "approve"
-    REJECT = "reject"
-
-
-class FeishuApprovalValueKey(StrEnum):
-    TICKET_ID = "ticket_id"
-    DECISION = "decision"
-    ACTION = "action"
-    COMMENT = "comment"
-
-
 class FeishuCardKey(StrEnum):
     ACTIONS = "actions"
     BUTTON_TYPE = "type"
@@ -123,10 +111,6 @@ FEISHU_AUTH_MISSING = "Feishu app credentials are not configured"
 FEISHU_VERIFICATION_TOKEN_REQUIRED = "FEISHU_VERIFICATION_TOKEN is required"
 FEISHU_INVALID_TOKEN = "Invalid Feishu token"
 FEISHU_RECEIVE_ID_MISSING = "receive_id or FEISHU_DEFAULT_CHAT_ID is required"
-FEISHU_APPROVAL_ACTION_INVALID = "Invalid Feishu approval action payload"
-FEISHU_APPROVAL_APPROVER_IDS_REQUIRED = "FEISHU_APPROVAL_APPROVER_IDS is required"
-FEISHU_APPROVER_NOT_ALLOWED = "Feishu approver is not allowed"
-FEISHU_APPROVAL_CARD_ACTION_TARGET = "approval_card_action"
 FEISHU_SUCCESS_CODE = 0
 FEISHU_DEFAULT_TOKEN_EXPIRE_SECONDS = 7200
 FEISHU_TOKEN_EXPIRE_SAFETY_SECONDS = 300