feat(usage): 使用记录增加计费模式字段 — 记录/展示/筛选 token/按次/图片

- DB: usage_logs 表新增 billing_mode VARCHAR(20) 列
- 后端: RecordUsage 写入时根据 image_count 判定计费模式
- 前端: 使用记录表格新增计费模式 badge 列 + 筛选下拉

frontend/src/components/admin/usage/UsageTable.vue

@@ -69,6 +69,12 @@
           </span>
         </template>
 
+        <template #cell-billing_mode="{ row }">
+          <span class="inline-flex items-center rounded px-2 py-0.5 text-xs font-medium" :class="getBillingModeBadgeClass(row.billing_mode)">
+            {{ getBillingModeLabel(row.billing_mode) }}
+          </span>
+        </template>
+
         <template #cell-tokens="{ row }">
           <!-- 图片生成请求 -->
           <div v-if="row.image_count > 0" class="flex items-center gap-1.5">
@@ -350,6 +356,18 @@ const getRequestTypeBadgeClass = (row: AdminUsageLog): string => {
   return 'bg-amber-100 text-amber-800 dark:bg-amber-900 dark:text-amber-200'
 }
 
+const getBillingModeLabel = (mode: string | null | undefined): string => {
+  if (mode === 'per_request') return t('admin.usage.billingModePerRequest')
+  if (mode === 'image') return t('admin.usage.billingModeImage')
+  return t('admin.usage.billingModeToken')
+}
+
+const getBillingModeBadgeClass = (mode: string | null | undefined): string => {
+  if (mode === 'per_request') return 'bg-blue-100 text-blue-800 dark:bg-blue-900 dark:text-blue-200'
+  if (mode === 'image') return 'bg-green-100 text-green-800 dark:bg-green-900 dark:text-green-200'
+  return 'bg-gray-100 text-gray-800 dark:bg-gray-700 dark:text-gray-200'
+}
+
 const formatCacheTokens = (tokens: number): string => {
   if (tokens >= 1000000) return `${(tokens / 1000000).toFixed(1)}M`
   if (tokens >= 1000) return `${(tokens / 1000).toFixed(1)}K`

frontend/src/i18n/locales/en.ts

@@ -3356,6 +3356,11 @@ export default {
       allBillingTypes: 'All Billing Types',
       billingTypeBalance: 'Balance',
       billingTypeSubscription: 'Subscription',
+      billingMode: 'Billing Mode',
+      billingModeToken: 'Token',
+      billingModePerRequest: 'Per Request',
+      billingModeImage: 'Image',
+      allBillingModes: 'All Billing Modes',
       ipAddress: 'IP',
       clickToViewBalance: 'Click to view balance history',
       failedToLoadUser: 'Failed to load user info',

frontend/src/i18n/locales/zh.ts

@@ -3515,6 +3515,11 @@ export default {
       allBillingTypes: '全部计费类型',
       billingTypeBalance: '钱包余额',
       billingTypeSubscription: '订阅套餐',
+      billingMode: '计费模式',
+      billingModeToken: '按量',
+      billingModePerRequest: '按次',
+      billingModeImage: '按次(图片)',
+      allBillingModes: '全部计费模式',
       ipAddress: 'IP',
       clickToViewBalance: '点击查看充值记录',
       failedToLoadUser: '加载用户信息失败',

frontend/src/types/index.ts

@@ -1036,6 +1036,9 @@ export interface UsageLog {
   // Cache TTL Override
   cache_ttl_overridden: boolean
 
+  // 计费模式
+  billing_mode?: string | null
+
   created_at: string
 
   user?: User

frontend/src/views/admin/UsageView.vue

@@ -392,7 +392,7 @@ const resetFilters = () => {
   const range = getLast24HoursRangeDates()
   startDate.value = range.start
   endDate.value = range.end
-  filters.value = { start_date: startDate.value, end_date: endDate.value, request_type: undefined, billing_type: null }
+  filters.value = { start_date: startDate.value, end_date: endDate.value, request_type: undefined, billing_type: null, billing_mode: undefined }
   granularity.value = getGranularityForRange(startDate.value, endDate.value)
   applyFilters()
 }
@@ -477,6 +477,7 @@ const allColumns = computed(() => [
   { key: 'endpoint', label: t('usage.endpoint'), sortable: false },
   { key: 'group', label: t('admin.usage.group'), sortable: false },
   { key: 'stream', label: t('usage.type'), sortable: false },
+  { key: 'billing_mode', label: t('admin.usage.billingMode'), sortable: false },
   { key: 'tokens', label: t('usage.tokens'), sortable: false },
   { key: 'cost', label: t('usage.cost'), sortable: false },
   { key: 'first_token', label: t('usage.firstToken'), sortable: false },