fix: merge general improvements from release branch

Backend:
- gateway_handler: pass subject.UserID instead of int64(0) for user-level routing
- setting_handler: add missing BalanceLowNotifyRechargeURL to UpdateSettings response
- openai_gateway_service: use applyAccountStatsCost for account stats pricing integration
- embed_on: add local file override (data/public/) for embedded frontend assets

Frontend:
- useTableSelection: add batchUpdate method for batch operations
- AccountsView: virtual scrolling params, Set-based isSelected, swipe virtualization
- ProxiesView: add batchUpdate to selection and swipe-select
- BulkEditAccountModal: fix submit handler to prevent event object as argument
- SettingsView: move payload construction outside try block
- i18n: add general translation keys (saved, deleted, view, validation, allowUserRefund)
- api/client: reorder error fields for consistency
- stores/payment: clarify pollOrderStatus JSDoc

backend/internal/service/openai_gateway_service.go

@@ -4575,14 +4575,9 @@ func (s *OpenAIGatewayService) RecordUsage(ctx context.Context, input *OpenAIRec
 
 	// 计算账号统计定价费用（使用最终上游模型匹配自定义规则）
 	if apiKey.GroupID != nil {
-		statsModel := result.UpstreamModel
-		if statsModel == "" {
-			statsModel = result.Model
-		}
-		usageLog.AccountStatsCost = resolveAccountStatsCost(
-			ctx, s.channelService, s.billingService,
-			account.ID, *apiKey.GroupID, statsModel,
-			tokens, 1, cost.TotalCost,
+		applyAccountStatsCost(ctx, usageLog, s.channelService, s.billingService,
+			account.ID, *apiKey.GroupID, result.UpstreamModel, result.Model,
+			tokens, cost.TotalCost,
 		)
 	}