feat(admin): add user balance/concurrency history modal

- Add new API endpoint GET /admin/users/:id/balance-history with pagination and type filter
- Add SumPositiveBalanceByUser for calculating total recharged amount
- Create UserBalanceHistoryModal component with:
  - User info header (email, username, created_at, current balance, notes, total recharged)
  - Type filter dropdown (all/balance/admin_balance/concurrency/admin_concurrency/subscription)
  - Quick deposit/withdraw buttons
  - Paginated history list with icons and colored values
- Add instant tooltip on balance column for better UX
- Add z-index prop to BaseDialog for modal stacking control
- Update i18n translations (zh/en)

frontend/src/views/admin/UsersView.vue

@@ -300,8 +300,29 @@
             </span>
           </template>
 
-          <template #cell-balance="{ value }">
-            <span class="font-medium text-gray-900 dark:text-white">${{ value.toFixed(2) }}</span>
+          <template #cell-balance="{ value, row }">
+            <div class="flex items-center gap-2">
+              <div class="group relative">
+                <button
+                  class="font-medium text-gray-900 underline decoration-dashed decoration-gray-300 underline-offset-4 transition-colors hover:text-primary-600 dark:text-white dark:decoration-dark-500 dark:hover:text-primary-400"
+                  @click="handleBalanceHistory(row)"
+                >
+                  ${{ value.toFixed(2) }}
+                </button>
+                <!-- Instant tooltip -->
+                <div class="pointer-events-none absolute bottom-full left-1/2 z-50 mb-1.5 -translate-x-1/2 whitespace-nowrap rounded bg-gray-900 px-2 py-1 text-xs text-white opacity-0 shadow-lg transition-opacity duration-75 group-hover:opacity-100 dark:bg-dark-600">
+                  {{ t('admin.users.balanceHistoryTip') }}
+                  <div class="absolute left-1/2 top-full -translate-x-1/2 border-4 border-transparent border-t-gray-900 dark:border-t-dark-600"></div>
+                </div>
+              </div>
+              <button
+                @click.stop="handleDeposit(row)"
+                class="rounded px-2 py-0.5 text-xs font-medium text-emerald-600 transition-colors hover:bg-emerald-50 dark:text-emerald-400 dark:hover:bg-emerald-900/20"
+                :title="t('admin.users.deposit')"
+              >
+                {{ t('admin.users.deposit') }}
+              </button>
+            </div>
           </template>
 
           <template #cell-usage="{ row }">
@@ -456,6 +477,15 @@
                 {{ t('admin.users.withdraw') }}
               </button>
 
+              <!-- Balance History -->
+              <button
+                @click="handleBalanceHistory(user); closeActionMenu()"
+                class="flex w-full items-center gap-2 px-4 py-2 text-sm text-gray-700 hover:bg-gray-100 dark:text-gray-300 dark:hover:bg-dark-700"
+              >
+                <Icon name="dollar" size="sm" class="text-gray-400" :stroke-width="2" />
+                {{ t('admin.users.balanceHistory') }}
+              </button>
+
               <div class="my-1 border-t border-gray-100 dark:border-dark-700"></div>
 
               <!-- Delete (not for admin) -->
@@ -479,6 +509,7 @@
     <UserApiKeysModal :show="showApiKeysModal" :user="viewingUser" @close="closeApiKeysModal" />
     <UserAllowedGroupsModal :show="showAllowedGroupsModal" :user="allowedGroupsUser" @close="closeAllowedGroupsModal" @success="loadUsers" />
     <UserBalanceModal :show="showBalanceModal" :user="balanceUser" :operation="balanceOperation" @close="closeBalanceModal" @success="loadUsers" />
+    <UserBalanceHistoryModal :show="showBalanceHistoryModal" :user="balanceHistoryUser" @close="closeBalanceHistoryModal" @deposit="handleDepositFromHistory" @withdraw="handleWithdrawFromHistory" />
     <UserAttributesConfigModal :show="showAttributesModal" @close="handleAttributesModalClose" />
   </AppLayout>
 </template>
@@ -509,6 +540,7 @@ import UserEditModal from '@/components/admin/user/UserEditModal.vue'
 import UserApiKeysModal from '@/components/admin/user/UserApiKeysModal.vue'
 import UserAllowedGroupsModal from '@/components/admin/user/UserAllowedGroupsModal.vue'
 import UserBalanceModal from '@/components/admin/user/UserBalanceModal.vue'
+import UserBalanceHistoryModal from '@/components/admin/user/UserBalanceHistoryModal.vue'
 
 const appStore = useAppStore()
 
@@ -828,6 +860,10 @@ const showBalanceModal = ref(false)
 const balanceUser = ref<AdminUser | null>(null)
 const balanceOperation = ref<'add' | 'subtract'>('add')
 
+// Balance History modal state
+const showBalanceHistoryModal = ref(false)
+const balanceHistoryUser = ref<AdminUser | null>(null)
+
 // 计算剩余天数
 const getDaysRemaining = (expiresAt: string): number => {
   const now = new Date()
@@ -1078,6 +1114,30 @@ const closeBalanceModal = () => {
   balanceUser.value = null
 }
 
+const handleBalanceHistory = (user: AdminUser) => {
+  balanceHistoryUser.value = user
+  showBalanceHistoryModal.value = true
+}
+
+const closeBalanceHistoryModal = () => {
+  showBalanceHistoryModal.value = false
+  balanceHistoryUser.value = null
+}
+
+// Handle deposit from balance history modal
+const handleDepositFromHistory = () => {
+  if (balanceHistoryUser.value) {
+    handleDeposit(balanceHistoryUser.value)
+  }
+}
+
+// Handle withdraw from balance history modal
+const handleWithdrawFromHistory = () => {
+  if (balanceHistoryUser.value) {
+    handleWithdraw(balanceHistoryUser.value)
+  }
+}
+
 // 滚动时关闭菜单
 const handleScroll = () => {
   closeActionMenu()