Merge upstream/main into feat/grok-complete-integration

冲突集中在 chat completions / messages 两条 Responses 转发路径：
upstream 给 OpenAIForwardResult 增加了 UpstreamResponseModel 与
UpstreamResponseModelConflict（配套 beginUpstreamResponseModelObservation
观测器），本分支在同样位置把返回值改成了具名变量以便挂 Grok 原生搜索计数。
两侧不互斥，合并结果同时保留上游的响应模型观测字段与 Grok SearchCount 逻辑。

frontend/pnpm-lock.yaml 取 upstream 版本：package.json 与 upstream 完全一致，
本地差异只是 pnpm install 的重解析噪音。

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

@@ -139,6 +139,11 @@
           <Select v-model="filters.billing_mode" :options="billingModeOptions" @change="emitChange" />
         </div>
 
+        <div v-if="mode === 'usage'" class="w-full sm:w-auto sm:min-w-[220px]">
+          <label class="input-label">{{ t('admin.usage.upstreamModelAudit') }}</label>
+          <Select v-model="filters.upstream_model_mismatch" :options="upstreamModelMismatchOptions" @change="emitChange" />
+        </div>
+
         <!-- Error Phase Filter (errors only) -->
         <div v-if="mode === 'errors'" class="w-full sm:w-auto sm:min-w-[180px]">
           <label class="input-label">{{ t('admin.ops.errorLog.type') }}</label>
@@ -307,6 +312,12 @@ const billingModeOptions = ref<SelectOption[]>([
   { value: 'video', label: t('admin.usage.billingModeVideo') }
 ])
 
+const upstreamModelMismatchOptions = ref<SelectOption[]>([
+  { value: null, label: t('admin.usage.allUpstreamModelAudit') },
+  { value: true, label: t('admin.usage.upstreamModelMismatchOnly') },
+  { value: false, label: t('admin.usage.upstreamModelMatchedOnly') }
+])
+
 const emitChange = () => emit('change')
 
 const clearPendingUserSearch = () => {

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

@@ -53,23 +53,41 @@
         </template>
 
         <template #cell-model="{ row }">
-          <div v-if="row.model_mapping_chain && row.model_mapping_chain.includes('→')" class="space-y-0.5 text-xs">
-            <div v-for="(step, i) in row.model_mapping_chain.split('→')" :key="i"
-                 class="break-all"
-                 :class="i === 0 ? 'font-medium text-gray-900 dark:text-white' : 'text-gray-500 dark:text-gray-400'"
-                 :style="i > 0 ? `padding-left: ${i * 0.75}rem` : ''">
-              <span v-if="i > 0" class="mr-0.5">↳</span>{{ step }}
+          <div class="space-y-0.5 text-xs">
+            <div v-if="row.model_mapping_chain && row.model_mapping_chain.includes('→')" class="space-y-0.5">
+              <div v-for="(step, i) in row.model_mapping_chain.split('→')" :key="i"
+                   class="break-all"
+                   :class="i === 0 ? 'font-medium text-gray-900 dark:text-white' : 'text-gray-500 dark:text-gray-400'"
+                   :style="i > 0 ? `padding-left: ${i * 0.75}rem` : ''">
+                <span v-if="i > 0" class="mr-0.5">↳</span>{{ step }}
+              </div>
+            </div>
+            <div v-else-if="row.upstream_model && row.upstream_model !== row.model" class="space-y-0.5">
+              <div class="break-all font-medium text-gray-900 dark:text-white">
+                {{ row.model }}
+              </div>
+              <div class="break-all text-gray-500 dark:text-gray-400">
+                <span class="mr-0.5">↳</span>{{ row.upstream_model }}
+              </div>
+            </div>
+            <span v-else class="font-medium text-gray-900 dark:text-white">{{ row.model }}</span>
+            <div
+              v-if="row.upstream_model_mismatch === true && row.upstream_response_model"
+              class="break-all pl-3 text-[11px]"
+              :class="isLikelyModelVariant(row) ? 'text-amber-600 dark:text-amber-400' : 'text-orange-600 dark:text-orange-400'"
+              :title="modelAuditTitle(row)"
+            >
+              <span class="mr-1">↳ {{ t('usage.upstreamResponseModel') }}:</span>{{ row.upstream_response_model }}
+              <span
+                class="ml-1 inline-flex rounded px-1 py-px text-[10px] font-medium ring-1 ring-inset"
+                :class="isLikelyModelVariant(row)
+                  ? 'bg-amber-50 text-amber-700 ring-amber-200 dark:bg-amber-500/10 dark:text-amber-300 dark:ring-amber-500/30'
+                  : 'bg-orange-50 text-orange-700 ring-orange-200 dark:bg-orange-500/10 dark:text-orange-300 dark:ring-orange-500/30'"
+              >
+                {{ isLikelyModelVariant(row) ? t('usage.modelVariant') : t('usage.modelMismatch') }}
+              </span>
             </div>
           </div>
-          <div v-else-if="row.upstream_model && row.upstream_model !== row.model" class="space-y-0.5 text-xs">
-            <div class="break-all font-medium text-gray-900 dark:text-white">
-              {{ row.model }}
-            </div>
-            <div class="break-all text-gray-500 dark:text-gray-400">
-              <span class="mr-0.5">↳</span>{{ row.upstream_model }}
-            </div>
-          </div>
-          <span v-else class="font-medium text-gray-900 dark:text-white">{{ row.model }}</span>
         </template>
 
         <template #cell-reasoning_effort="{ row }">
@@ -548,6 +566,27 @@ const ipGeoBatchLoading = ref(false)
 
 const showIpGeoToolbar = computed(() => props.columns.some((col) => col.key === 'ip_address'))
 
+const sentUpstreamModel = (row: AdminUsageLog): string => row.upstream_model?.trim() || row.model?.trim() || ''
+
+const normalizeModelVariant = (model: string): string => model
+  .trim()
+  .toLowerCase()
+  .replace(/-latest$/, '')
+  .replace(/-\d{4}-\d{2}-\d{2}$/, '')
+  .replace(/-\d{8}$/, '')
+
+const isLikelyModelVariant = (row: AdminUsageLog): boolean => {
+  const sent = sentUpstreamModel(row)
+  const response = row.upstream_response_model?.trim() || ''
+  return sent !== '' && response !== '' && normalizeModelVariant(sent) === normalizeModelVariant(response)
+}
+
+const modelAuditTitle = (row: AdminUsageLog): string => [
+  `${t('usage.requestedModel')}: ${row.model || '-'}`,
+  `${t('usage.sentUpstreamModel')}: ${sentUpstreamModel(row) || '-'}`,
+  `${t('usage.upstreamResponseModel')}: ${row.upstream_response_model || '-'}`,
+].join('\n')
+
 const currentPageIps = computed(() =>
   Array.from(new Set(props.data.map((row) => row.ip_address).filter((ip): ip is string => Boolean(ip))))
 )

frontend/src/components/admin/usage/__tests__/UsageFilters.spec.ts

@@ -28,6 +28,10 @@ const messages: Record<string, string> = {
   'admin.usage.billingModeToken': 'Token',
   'admin.usage.billingModePerRequest': 'Per Request',
   'admin.usage.billingModeImage': 'Image',
+	'admin.usage.upstreamModelAudit': 'Upstream model audit',
+	'admin.usage.allUpstreamModelAudit': 'All response model states',
+	'admin.usage.upstreamModelMismatchOnly': 'Mismatched only',
+	'admin.usage.upstreamModelMatchedOnly': 'Matched only',
   'admin.usage.group': 'Group',
   'admin.usage.allGroups': 'All Groups',
   'common.refresh': 'Refresh',
@@ -75,6 +79,7 @@ const defaultFilters = () => ({
   request_type: null,
   billing_type: null,
   billing_mode: null,
+	upstream_model_mismatch: null,
   group_id: null,
   start_date: '',
   end_date: '',

frontend/src/components/admin/usage/__tests__/UsageTable.spec.ts

@@ -51,6 +51,11 @@ const messages: Record<string, string> = {
   'admin.usage.billingModeToken': 'Token',
   'admin.usage.billingModePerRequest': 'Per request',
   'admin.usage.billingModeImage': 'Image',
+	'usage.requestedModel': 'Requested',
+	'usage.sentUpstreamModel': 'Sent upstream',
+	'usage.upstreamResponseModel': 'Upstream response',
+	'usage.modelVariant': 'Possible version variant',
+	'usage.modelMismatch': 'Different model',
 }
 
 vi.mock('vue-i18n', async () => {
@@ -240,6 +245,48 @@ describe('admin UsageTable tooltip', () => {
     expect(text).toContain('claude-sonnet-4-20250514')
   })
 
+	it.each([
+		{
+			name: 'possible version variant',
+			responseModel: 'gpt-5.5-2026-08-01',
+			expectedBadge: 'Possible version variant',
+		},
+		{
+			name: 'different upstream model',
+			responseModel: 'gpt-5.4',
+			expectedBadge: 'Different model',
+		},
+	])('shows a compact upstream response audit marker for $name', ({ responseModel, expectedBadge }) => {
+		const wrapper = mount(UsageTable, {
+			props: {
+				data: [{
+					request_id: `req-${responseModel}`,
+					model: 'gpt-5.6-sol',
+					upstream_model: 'gpt-5.5',
+					model_mapping_chain: 'gpt-5.6-sol→gpt-5.5',
+					upstream_response_model: responseModel,
+					upstream_model_mismatch: true,
+				}],
+				loading: false,
+				columns: [],
+			},
+			global: {
+				stubs: {
+					DataTable: DataTableStub,
+					EmptyState: true,
+					Icon: true,
+					Teleport: true,
+				},
+			},
+		})
+
+		const text = wrapper.text()
+		expect(text).toContain('gpt-5.6-sol')
+		expect(text).toContain('gpt-5.5')
+		expect(text).toContain(responseModel)
+		expect(text).toContain(expectedBadge)
+	})
+
   it.each([
     {
       name: 'defaulted row',