feat(员工代收款): 新增员工代收款账单闭环

- 新增 6 张表与成对迁移 000212，扩展企业微信审批场景业务类型白名单
- 后台线下套餐订单与两条代理线下充值入账路径在来源成功事务内建账，来源唯一键幂等
- 核销申请、审批尝试记录、账单分摊预占与驳回重提，审批业务类型 employee_collection_approval
- 企业微信终态消费幂等：通过转已核销、驳回释放预占、通过后撤销不回滚并转异常终态
- 退款成功事务内按 bill_id+refund_id 幂等冲销账单或仅写退款关联提示
- 线下收款方式字典、账单查询/统计/关闭、申请查询与代办权限，均写入事务内审计

OpenSpec Change: add-employee-collection-bills

internal/application/wecom/scene.go

@@ -333,6 +333,22 @@ func sceneBusinessFields(businessType string) ([]dto.WeComBusinessFieldResponse,
 			{Code: constants.ApprovalFieldSubmitterID, Name: "提交人账号 ID", ValueType: constants.ApprovalFieldValueTypeInteger, Description: "本系统真实业务提交人账号 ID"},
 			{Code: constants.ApprovalFieldSubmitterName, Name: "提交人名称", ValueType: constants.ApprovalFieldValueTypeString, Description: "本系统真实业务提交人名称快照"},
 		}, true
+	case constants.ApprovalBusinessTypeEmployeeCollection:
+		return []dto.WeComBusinessFieldResponse{
+			{Code: constants.ApprovalFieldCollectionApplicationID, Name: "核销申请 ID", ValueType: constants.ApprovalFieldValueTypeInteger, Description: "员工代收款核销申请的系统 ID"},
+			{Code: constants.ApprovalFieldCollectionPaymentMethod, Name: "线下收款方式", ValueType: constants.ApprovalFieldValueTypeString, Description: "本次外部付款使用的线下收款方式名称快照"},
+			{Code: constants.ApprovalFieldCollectionPaidAmount, Name: "付款金额", ValueType: constants.ApprovalFieldValueTypeMoney, Description: "以元为单位且保留两位小数的人工确认付款金额"},
+			{Code: constants.ApprovalFieldCollectionPaidAmountCent, Name: "付款金额（分）", ValueType: constants.ApprovalFieldValueTypeInteger, Description: "以分为单位的人工确认付款金额整数"},
+			{Code: constants.ApprovalFieldCollectionPayerName, Name: "付款方", ValueType: constants.ApprovalFieldValueTypeString, Description: "本次外部付款的付款方名称"},
+			{Code: constants.ApprovalFieldCollectionPaidAt, Name: "付款时间", ValueType: constants.ApprovalFieldValueTypeString, Description: "本次外部付款时间，RFC3339 格式"},
+			{Code: constants.ApprovalFieldCollectionExternalTransactionNo, Name: "外部交易流水号", ValueType: constants.ApprovalFieldValueTypeString, Description: "人工确认的第三方交易流水号，用于审批人核验"},
+			{Code: constants.ApprovalFieldPaymentVoucherKey, Name: "付款凭证", ValueType: constants.ApprovalFieldValueTypeFileList, Description: "提交时上传到企微文件控件的付款凭证列表"},
+			{Code: constants.ApprovalFieldRemark, Name: "备注", ValueType: constants.ApprovalFieldValueTypeString, Description: "申请人填写的核销备注"},
+			{Code: constants.ApprovalFieldCollectionBillCount, Name: "分摊账单数量", ValueType: constants.ApprovalFieldValueTypeInteger, Description: "本次核销分摊的账单数量"},
+			{Code: constants.ApprovalFieldCollectionBillSummary, Name: "账单分摊摘要", ValueType: constants.ApprovalFieldValueTypeString, Description: "本次各账单应收金额与分摊金额摘要"},
+			{Code: constants.ApprovalFieldSubmitterID, Name: "提交人账号 ID", ValueType: constants.ApprovalFieldValueTypeInteger, Description: "本系统真实业务提交人账号 ID"},
+			{Code: constants.ApprovalFieldSubmitterName, Name: "提交人名称", ValueType: constants.ApprovalFieldValueTypeString, Description: "本系统真实业务提交人名称快照"},
+		}, true
 	default:
 		return nil, false
 	}
@@ -353,14 +369,27 @@ func normalizeSceneMapping(mapping []dto.WeComControlMappingItem) []dto.WeComCon
 }
 
 func validApprovalBusinessType(businessType string) bool {
-	return businessType == constants.ApprovalBusinessTypeRefund || businessType == constants.ApprovalBusinessTypeOfflineRecharge
+	switch businessType {
+	case constants.ApprovalBusinessTypeRefund,
+		constants.ApprovalBusinessTypeOfflineRecharge,
+		constants.ApprovalBusinessTypeEmployeeCollection:
+		return true
+	default:
+		return false
+	}
 }
 
 func approvalBusinessTypeName(businessType string) string {
-	if businessType == constants.ApprovalBusinessTypeRefund {
+	switch businessType {
+	case constants.ApprovalBusinessTypeRefund:
 		return "退款审批"
+	case constants.ApprovalBusinessTypeOfflineRecharge:
+		return "员工线下代充值审批"
+	case constants.ApprovalBusinessTypeEmployeeCollection:
+		return "员工代收款核销审批"
+	default:
+		return "未知审批业务类型"
 	}
-	return "员工线下代充值审批"
 }
 
 func sceneAuditSnapshot(scene *model.WeComApprovalScene) map[string]any {