feat(代理自充): AUG26-017 代理自充收款方式与线下预存款审批字段

- 受控配置新增代理在线自充允许范围（仅微信/仅支付宝/同时支持），读侧与创建侧取允许范围与可用商户池交集，两侧失败关闭
- 新增允许范围查询与修改端点，读限代理与平台账号、写限超级管理员，复用受控配置写服务留痕
- tb_agent_recharge_record 新增交易流水号、线下收款方式三列快照与其他凭证列（成对迁移 000213）
- 线下申请校验启用的收款方式字典项与必填交易流水号，交易流水号独立于在线渠道交易号、不参与去重
- 扩展 offline_recharge_approval 场景可映射字段白名单与字典引用保护
- 新增付款凭证识别能力与交易流水号预填接口，识别不落库、日志不记录载荷

internal/bootstrap/payment_method_config.go

@@ -15,6 +15,7 @@ func registerPaymentMethodConfigDefinitions(registry *systemconfig.Registry, log
 	definitions := []systemconfig.Definition{
 		{Key: constants.SystemConfigPaymentAllowedCard, Module: constants.SystemConfigModulePayment, ValueType: constants.SystemConfigTypeJSON, DefaultValue: `["wallet","wechat","alipay"]`, Description: "卡资产允许的C端支付方式", Control: "payment_methods", Validator: paymentmethod.ValidateConfigValue},
 		{Key: constants.SystemConfigPaymentAllowedDevice, Module: constants.SystemConfigModulePayment, ValueType: constants.SystemConfigTypeJSON, DefaultValue: `["wallet","wechat","alipay"]`, Description: "设备资产允许的C端支付方式", Control: "payment_methods", Validator: paymentmethod.ValidateConfigValue},
+		{Key: constants.SystemConfigAgentSelfRechargeAllowedMethods, Module: constants.SystemConfigModulePayment, ValueType: constants.SystemConfigTypeString, DefaultValue: constants.AgentSelfRechargeAllowedBoth, Description: "代理在线自充允许的支付方式范围", Control: "payment_methods", EnumValues: []string{constants.AgentSelfRechargeAllowedWechatOnly, constants.AgentSelfRechargeAllowedAlipayOnly, constants.AgentSelfRechargeAllowedBoth}},
 	}
 	for _, definition := range definitions {
 		if existing, exists := registry.Get(definition.Key); exists {