feat: 完善使用记录端点可观测性与分布统计

将入站、上游与路径三类端点分布统一到使用记录页的一致化卡片交互中，并补齐端点元数据与统计链路，提升排障与流量分析效率。

frontend/src/components/admin/account/AccountStatsModal.vue

@@ -410,6 +410,18 @@
 
         <!-- Model Distribution -->
         <ModelDistributionChart :model-stats="stats.models" :loading="false" />
+
+        <EndpointDistributionChart
+          :endpoint-stats="stats.endpoints || []"
+          :loading="false"
+          :title="t('usage.inboundEndpoint')"
+        />
+
+        <EndpointDistributionChart
+          :endpoint-stats="stats.upstream_endpoints || []"
+          :loading="false"
+          :title="t('usage.upstreamEndpoint')"
+        />
       </template>
 
       <!-- No Data State -->
@@ -453,6 +465,7 @@ import { Line } from 'vue-chartjs'
 import BaseDialog from '@/components/common/BaseDialog.vue'
 import LoadingSpinner from '@/components/common/LoadingSpinner.vue'
 import ModelDistributionChart from '@/components/charts/ModelDistributionChart.vue'
+import EndpointDistributionChart from '@/components/charts/EndpointDistributionChart.vue'
 import Icon from '@/components/icons/Icon.vue'
 import { adminAPI } from '@/api/admin'
 import type { Account, AccountUsageStatsResponse } from '@/types'

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

@@ -35,6 +35,19 @@
           </span>
         </template>
 
+        <template #cell-endpoint="{ row }">
+          <div class="max-w-[320px] space-y-1 text-xs">
+            <div class="break-all text-gray-700 dark:text-gray-300">
+              <span class="font-medium text-gray-500 dark:text-gray-400">{{ t('usage.inbound') }}:</span>
+              <span class="ml-1">{{ row.inbound_endpoint?.trim() || '-' }}</span>
+            </div>
+            <div class="break-all text-gray-700 dark:text-gray-300">
+              <span class="font-medium text-gray-500 dark:text-gray-400">{{ t('usage.upstream') }}:</span>
+              <span class="ml-1">{{ row.upstream_endpoint?.trim() || '-' }}</span>
+            </div>
+          </div>
+        </template>
+
         <template #cell-group="{ row }">
           <span v-if="row.group" class="inline-flex items-center rounded px-2 py-0.5 text-xs font-medium bg-indigo-100 text-indigo-800 dark:bg-indigo-900 dark:text-indigo-200">
             {{ row.group.name }}
@@ -328,6 +341,7 @@ const getRequestTypeBadgeClass = (row: AdminUsageLog): string => {
   if (requestType === 'sync') return 'bg-gray-100 text-gray-800 dark:bg-gray-700 dark:text-gray-200'
   return 'bg-amber-100 text-amber-800 dark:bg-amber-900 dark:text-amber-200'
 }
+
 const formatCacheTokens = (tokens: number): string => {
   if (tokens >= 1000000) return `${(tokens / 1000000).toFixed(1)}M`
   if (tokens >= 1000) return `${(tokens / 1000).toFixed(1)}K`