删除钱包充值功能并消除重复入账风险

钱包充值为开发态测试功能(生产环境本就禁用),且支付回调存在重复入账风险:入账与标记 paid 两步非原子、wallet_ledger 去重无唯一索引、幂等键使用了可变的 ProviderOrderID。直接删除该功能从根本上消除风险。

后端:
- payment 移除 StartWalletRecharge/QueryWalletRecharge 及相关 handler/DTO/常量;confirmPaid 增加 OrderID 守卫;解除对 wallet 仓库的依赖
- wallet 移除 Recharge/ConfirmRechargeFromChannel 及相关定义
- 移除三条充值路由;adminfinance 财务统计口径只统计 order_pay
- 清理充值相关测试用例

前端:
- 移除充值 API、WalletView 充值面板/弹窗、admin 充值标签与筛选
- 保留钱包余额、流水、提现等核心能力

go build/vet 与 vue-tsc typecheck 均通过。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/internal/modules/payment/repository_integration_test.go

@@ -271,39 +271,6 @@ func TestRefundAmountMustNotExceedOriginal(t *testing.T) {
 	}
 }
 
-// TestWalletRechargeEnabled 测试钱包充值开关
-func TestWalletRechargeEnabledInDevelopment(t *testing.T) {
-	svc := NewService(nil, "development")
-	if !svc.walletRechargeEnabled {
-		t.Fatal("wallet recharge should be enabled in development")
-	}
-}
-
-func TestWalletRechargeDisabledInProduction(t *testing.T) {
-	svc := NewService(nil, "production")
-	if svc.walletRechargeEnabled {
-		t.Fatal("wallet recharge should be disabled in production")
-	}
-}
-
-func TestWalletRechargeEnabledInTestEnv(t *testing.T) {
-	svc := NewService(nil, "test")
-	if !svc.walletRechargeEnabled {
-		t.Fatal("wallet recharge should be enabled in test env")
-	}
-}
-
-// TestMinWalletRechargeAmountIsReasonable 测试最小充值金额合理性
-func TestMinWalletRechargeAmountIsReasonable(t *testing.T) {
-	if MinWalletRechargeAmount <= 0 {
-		t.Fatal("MinWalletRechargeAmount should be positive")
-	}
-
-	if MinWalletRechargeAmount > 1.0 {
-		t.Fatalf("MinWalletRechargeAmount = %.2f, seems too high for minimum", MinWalletRechargeAmount)
-	}
-}
-
 // TestPaymentNotifyResultStructure 测试支付回调结果结构
 func TestNotifyResultHasRequiredFields(t *testing.T) {
 	result := NotifyResult{