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

frontend/src/components/account/BulkEditAccountModal.vue

@@ -5,7 +5,7 @@
     width="wide"
     @close="handleClose"
   >
-    <form id="bulk-edit-account-form" class="space-y-5" @submit.prevent="handleSubmit">
+    <form id="bulk-edit-account-form" class="space-y-5" @submit.prevent="() => handleSubmit()">
       <!-- Info -->
       <div class="rounded-lg bg-blue-50 p-4 dark:bg-blue-900/20">
         <p class="text-sm text-blue-700 dark:text-blue-400">