feat: 新增退款管理模块 — 完整的退款审批流程、佣金回扣和资产重置

新增退款申请全生命周期管理：创建/列表/详情/审批通过/拒绝/退回/重新提交
审批通过后异步执行佣金全额回扣（扣减各代理佣金钱包）和资产重置（套餐失效+停机+世代重置）
新增 tb_refund_request 表（迁移 000093）、RefundRequest Model、8 个 DTO
新增 Store/Service/Handler/路由注册，仅平台用户可访问

pkg/constants/wallet.go

@@ -23,11 +23,12 @@ const (
 
 // 代理钱包交易类型
 const (
-	AgentTransactionTypeRecharge   = "recharge"   // 充值
-	AgentTransactionTypeDeduct     = "deduct"     // 扣款
-	AgentTransactionTypeRefund     = "refund"     // 退款
-	AgentTransactionTypeCommission = "commission" // 分佣
-	AgentTransactionTypeWithdrawal = "withdrawal" // 提现
+	AgentTransactionTypeRecharge         = "recharge"          // 充值
+	AgentTransactionTypeDeduct           = "deduct"            // 扣款
+	AgentTransactionTypeRefund           = "refund"            // 退款
+	AgentTransactionTypeCommission       = "commission"        // 分佣
+	AgentTransactionTypeWithdrawal       = "withdrawal"        // 提现
+	AgentTransactionTypeCommissionDeduct = "commission_deduct" // 退款佣金回扣
 )
 
 // 代理钱包交易子类型（当 transaction_type = "deduct" 用于订单支付时）
@@ -112,6 +113,7 @@ const (
 	ReferenceTypeCommission = "commission" // 分佣
 	ReferenceTypeWithdrawal = "withdrawal" // 提现
 	ReferenceTypeTopup      = "topup"      // 充值
+	ReferenceTypeRefund     = "refund"     // 退款
 )
 
 // ========== Redis Key 生成函数 ==========