fix: 长上下文默认保持开启，并与 OpenAI 账号开关取交集

迁移默认 false 会让存量分组静默丢掉 ≥200k 阶梯与渠道多档价。
OpenAI 路径传入 Group 后，账号级 openai_long_context_billing_enabled 被顶掉。

- 列默认 TRUE，并对存量行回填
- 分组价卡不再手填 token 区间，勾选走官方/预设阶梯
- 分组开关与账号开关 AND；价卡 JSON 损坏时打 warn

frontend/src/components/admin/channel/PricingEntryCard.vue

@@ -134,8 +134,8 @@
             </div>
           </div>
 
-          <!-- Token intervals -->
-          <div class="mt-3">
+          <!-- Token intervals (channel-only; group long-context uses official presets) -->
+          <div v-if="!hideTokenIntervals" class="mt-3">
             <div class="flex items-center justify-between">
               <label class="text-xs font-medium text-gray-500 dark:text-gray-400">
                 {{ t('admin.channels.form.intervals') }}
@@ -245,10 +245,13 @@ import channelsAPI from '@/api/admin/channels'
 
 const { t } = useI18n()
 
-const props = defineProps<{
+const props = withDefaults(defineProps<{
   entry: PricingFormEntry
   platform?: string
-}>()
+  hideTokenIntervals?: boolean
+}>(), {
+  hideTokenIntervals: false,
+})
 
 const emit = defineEmits<{
   update: [entry: PricingFormEntry]

frontend/src/i18n/locales/en/admin/overview.ts

@@ -1007,9 +1007,9 @@ export default {
       },
       modelPricing: {
         title: 'Per-model group pricing',
-        description: 'Overrides channel and built-in prices for matching models. Use per-request tiers such as realtime, tts, and stt for audio.',
+        description: 'Overrides channel and built-in prices for matching models. Long-context tiers come from official presets — do not enter custom intervals. Use per-request tiers such as realtime, tts, and stt for audio.',
         longContext: 'Enable long-context tier pricing',
-        longContextHint: 'When disabled, token models always use the lowest configured tier.',
+        longContextHint: 'When checked, official/preset long-context tiers apply. When unchecked, token models stay on the first-tier base rate.',
         add: 'Add model price'
       },
       voicePricing: {

frontend/src/i18n/locales/zh/admin/overview.ts

@@ -1004,9 +1004,9 @@ export default {
       },
       modelPricing: {
         title: '分组逐模型定价',
-        description: '匹配模型后覆盖渠道和内置价格。音频可用按次层级配置 realtime、tts、stt。',
+        description: '匹配模型后覆盖渠道和内置价格。长上下文阶梯沿用官方/预设价卡，无需再手填区间。音频可用按次层级配置 realtime、tts、stt。',
         longContext: '启用长上下文阶梯定价',
-        longContextHint: '关闭时，Token 模型始终只使用配置的最低档。',
+        longContextHint: '勾选后按官方/预设阶梯计费；关闭则始终按第一档基础价。',
         add: '添加模型价格'
       },
       voicePricing: {

frontend/src/views/admin/GroupsView.vue

@@ -1499,7 +1499,7 @@
             <span><span class="block text-sm text-gray-700 dark:text-gray-300">{{ t("admin.groups.modelPricing.longContext") }}</span><span class="block text-xs text-gray-500">{{ t("admin.groups.modelPricing.longContextHint") }}</span></span>
           </label>
           <div class="mt-3 space-y-2">
-            <PricingEntryCard v-for="(entry, index) in createForm.model_pricing" :key="index" :entry="entry" :platform="createForm.platform" @update="createForm.model_pricing[index] = $event" @remove="createForm.model_pricing.splice(index, 1)" />
+            <PricingEntryCard v-for="(entry, index) in createForm.model_pricing" :key="index" :entry="entry" :platform="createForm.platform" hide-token-intervals @update="createForm.model_pricing[index] = $event" @remove="createForm.model_pricing.splice(index, 1)" />
           </div>
         </div>
 
@@ -3221,7 +3221,7 @@
             <span><span class="block text-sm text-gray-700 dark:text-gray-300">{{ t("admin.groups.modelPricing.longContext") }}</span><span class="block text-xs text-gray-500">{{ t("admin.groups.modelPricing.longContextHint") }}</span></span>
           </label>
           <div class="mt-3 space-y-2">
-            <PricingEntryCard v-for="(entry, index) in editForm.model_pricing" :key="index" :entry="entry" :platform="editForm.platform" @update="editForm.model_pricing[index] = $event" @remove="editForm.model_pricing.splice(index, 1)" />
+            <PricingEntryCard v-for="(entry, index) in editForm.model_pricing" :key="index" :entry="entry" :platform="editForm.platform" hide-token-intervals @update="editForm.model_pricing[index] = $event" @remove="editForm.model_pricing.splice(index, 1)" />
           </div>
         </div>
 
@@ -4527,7 +4527,10 @@ const groupPricingToAPI = (
       image_input_price: mTokToPerToken(entry.image_input_price),
       image_output_price: mTokToPerToken(entry.image_output_price),
       per_request_price: toNullableNumber(entry.per_request_price),
-      intervals: formIntervalsToAPI(entry.intervals || []),
+      intervals:
+        entry.billing_mode === "token"
+          ? []
+          : formIntervalsToAPI(entry.intervals || []),
     }));
 
 const { t } = useI18n();
@@ -5013,7 +5016,7 @@ const createForm = reactive({
   daily_limit_usd: null as number | null,
   weekly_limit_usd: null as number | null,
   monthly_limit_usd: null as number | null,
-  long_context_pricing_enabled: false,
+  long_context_pricing_enabled: true,
   model_pricing: [] as PricingFormEntry[],
   // 图片生成计费配置
   allow_image_generation: false,
@@ -5374,7 +5377,7 @@ const editForm = reactive({
   daily_limit_usd: null as number | null,
   weekly_limit_usd: null as number | null,
   monthly_limit_usd: null as number | null,
-  long_context_pricing_enabled: false,
+  long_context_pricing_enabled: true,
   model_pricing: [] as PricingFormEntry[],
   // 图片生成计费配置
   allow_image_generation: false,
@@ -5848,7 +5851,7 @@ const closeCreateModal = () => {
   createForm.video_price_720p = null;
   createForm.video_price_1080p = null;
   createForm.video_model_prices = createVideoModelPricesForm();
-  createForm.long_context_pricing_enabled = false;
+  createForm.long_context_pricing_enabled = true;
   createForm.model_pricing = [];
   createForm.web_search_price_per_call = null;
   createForm.search_price_per_1k = null;
@@ -6076,7 +6079,7 @@ const handleEdit = async (group: AdminGroup) => {
   editForm.weekly_limit_usd = group.weekly_limit_usd;
   editForm.monthly_limit_usd = group.monthly_limit_usd;
   editForm.long_context_pricing_enabled =
-    group.long_context_pricing_enabled ?? false;
+    group.long_context_pricing_enabled ?? true;
   editForm.model_pricing = groupPricingFromAPI(group.model_pricing);
   editForm.allow_image_generation = group.allow_image_generation ?? false;
   editForm.allow_batch_image_generation =
@@ -6182,7 +6185,7 @@ const closeEditModal = () => {
   editForm.video_price_720p = null;
   editForm.video_price_1080p = null;
   editForm.video_model_prices = createVideoModelPricesForm();
-  editForm.long_context_pricing_enabled = false;
+  editForm.long_context_pricing_enabled = true;
   editForm.model_pricing = [];
   editForm.web_search_price_per_call = null;
   editForm.search_price_per_1k = null;