fix(channels): 按次/图片计费模式跳过 token 区间重叠校验

image 与 per_request 模式的层级按 tier_label (1K/2K/4K) 匹配,
不依赖 min/max token 范围, 多个层级共用 min=0/max=null 是预期形态。
原校验器一律按 token 上下文分段处理, 新增第二条图片层级时会被
"无上限区间只能是最后一个" 误拦, 导致 OpenAI gpt-image 等模型
无法保存按次定价。

validateIntervals 新增 mode 参数, image / per_request 模式跳过
区间重叠与 last-unlimited 检查, 保留单条 min/max 自洽与价格非负
校验。token 模式行为不变。

frontend/src/components/admin/channel/__tests__/types.spec.ts

@@ -0,0 +1,79 @@
+import { describe, expect, it } from 'vitest'
+import { validateIntervals, type IntervalFormEntry } from '../types'
+
+function makeInterval(over: Partial<IntervalFormEntry>): IntervalFormEntry {
+  return {
+    min_tokens: 0,
+    max_tokens: null,
+    tier_label: '',
+    input_price: null,
+    output_price: null,
+    cache_write_price: null,
+    cache_read_price: null,
+    per_request_price: null,
+    sort_order: 0,
+    ...over,
+  }
+}
+
+describe('validateIntervals', () => {
+  describe('token mode', () => {
+    it('rejects unbounded interval that is not last', () => {
+      const intervals: IntervalFormEntry[] = [
+        makeInterval({ min_tokens: 0, max_tokens: null, input_price: 1, output_price: 1 }),
+        makeInterval({ min_tokens: 200000, max_tokens: 500000, input_price: 2, output_price: 2 }),
+      ]
+      expect(validateIntervals(intervals, 'token')).toMatch(/无上限/)
+    })
+
+    it('accepts unbounded interval at the end', () => {
+      const intervals: IntervalFormEntry[] = [
+        makeInterval({ min_tokens: 0, max_tokens: 200000, input_price: 1, output_price: 1 }),
+        makeInterval({ min_tokens: 200000, max_tokens: null, input_price: 2, output_price: 2 }),
+      ]
+      expect(validateIntervals(intervals, 'token')).toBeNull()
+    })
+
+    it('rejects overlapping intervals', () => {
+      const intervals: IntervalFormEntry[] = [
+        makeInterval({ min_tokens: 0, max_tokens: 250000, input_price: 1, output_price: 1 }),
+        makeInterval({ min_tokens: 200000, max_tokens: 500000, input_price: 2, output_price: 2 }),
+      ]
+      expect(validateIntervals(intervals, 'token')).toMatch(/重叠/)
+    })
+
+    it('defaults mode to token when omitted', () => {
+      const intervals: IntervalFormEntry[] = [
+        makeInterval({ min_tokens: 0, max_tokens: null, input_price: 1, output_price: 1 }),
+        makeInterval({ min_tokens: 100, max_tokens: 200, input_price: 2, output_price: 2 }),
+      ]
+      expect(validateIntervals(intervals)).toMatch(/无上限/)
+    })
+  })
+
+  describe('image / per_request mode', () => {
+    it('allows multiple unbounded tiers identified by label', () => {
+      const intervals: IntervalFormEntry[] = [
+        makeInterval({ tier_label: '1K', per_request_price: 0.04 }),
+        makeInterval({ tier_label: '2K', per_request_price: 0.06 }),
+        makeInterval({ tier_label: '4K', per_request_price: 0.08 }),
+      ]
+      expect(validateIntervals(intervals, 'image')).toBeNull()
+      expect(validateIntervals(intervals, 'per_request')).toBeNull()
+    })
+
+    it('still rejects negative prices', () => {
+      const intervals: IntervalFormEntry[] = [
+        makeInterval({ tier_label: '1K', per_request_price: -1 }),
+      ]
+      expect(validateIntervals(intervals, 'image')).toMatch(/不能为负数/)
+    })
+
+    it('still rejects max <= min on a single tier', () => {
+      const intervals: IntervalFormEntry[] = [
+        makeInterval({ tier_label: '1K', min_tokens: 100, max_tokens: 50, per_request_price: 0.04 }),
+      ]
+      expect(validateIntervals(intervals, 'image')).toMatch(/必须大于/)
+    })
+  })
+})

frontend/src/components/admin/channel/types.ts

@@ -115,8 +115,17 @@ export function findModelConflict(models: string[]): [string, string] | null {
 
 // ── 区间校验 ──────────────────────────────────────────────
 
-/** 校验区间列表的合法性，返回错误消息；通过则返回 null */
-export function validateIntervals(intervals: IntervalFormEntry[]): string | null {
+/** 校验区间列表的合法性，返回错误消息；通过则返回 null
+ *
+ * mode 决定区间语义：
+ * - token：区间是上下文 token 数分段 (min, max]，不能重叠，无上限段必须放最后
+ * - per_request / image：区间是按 tier_label 分层（1K/2K/4K 等），后端按 label
+ *   匹配，不依赖 min/max，因此跳过重叠 / last-unlimited 校验
+ */
+export function validateIntervals(
+  intervals: IntervalFormEntry[],
+  mode: BillingMode = 'token',
+): string | null {
   if (!intervals || intervals.length === 0) return null
 
   // 按 min_tokens 排序（不修改原数组）
@@ -126,6 +135,9 @@ export function validateIntervals(intervals: IntervalFormEntry[]): string | null
     const err = validateSingleInterval(sorted[i], i)
     if (err) return err
   }
+
+  // per_request / image 模式按 tier_label 匹配，不做 token 区间重叠校验
+  if (mode !== 'token') return null
   return checkIntervalOverlap(sorted)
 }
 

frontend/src/views/admin/ChannelsView.vue

@@ -1418,7 +1418,7 @@ async function handleSubmit() {
   for (const section of form.platforms.filter(s => s.enabled)) {
     for (const entry of section.model_pricing) {
       if (!entry.intervals || entry.intervals.length === 0) continue
-      const intervalErr = validateIntervals(entry.intervals)
+      const intervalErr = validateIntervals(entry.intervals, entry.billing_mode)
       if (intervalErr) {
         const platformLabel = t('admin.groups.platforms.' + section.platform, section.platform)
         const modelLabel = entry.models.join(', ') || t('admin.channels.form.unnamed')