feat(viral-video): 积分动态预估——调用 /viral-video/estimate-credits，STEP3参数变化防抖300ms刷新，402积分不足提示

- 新增 estimateViralVideoCredits API 封装（POST /api/v1/viral-video/estimate-credits）
- TabTask 新增 estimatedCredits / estimatedCreditsError 两个字段
- STEP2文案完成(step2_copy_ready)后首次拉取；STEP3视频模型/清晰度/比例/时长变化防抖300ms重拉
- 接口失败显示「-- 积分」，加载中显示「… 积分」，不阻断操作
- 提交生成视频时识别 402 Payment Required，message.error 显示后端文案（默认「积分不足，请充值」）
- 未到STEP2阶段不显示积分区域

apps/web/src/api/viral-video/index.ts

@@ -51,6 +51,17 @@ export function analyzeViralStyle(id: string) {
   return apiClient.post<ViralVideoJob>(`/viral-video/${id}/analyze-style`).then((r) => r.data)
 }
 
+/** 动态预估积分消耗（STEP3 参数变化时调用） */
+export function estimateViralVideoCredits(params: {
+  video_model: string
+  resolution: string
+  video_ratio: string
+  duration: number
+}) {
+  return apiClient
+    .post<{ estimated_credits: number }>("/viral-video/estimate-credits", params)
+    .then((r) => r.data)
+}
 /** ── 三步拆分：前端 mock 辅助函数（后端新接口上线后可替换） ── */
 
 /**

apps/web/src/pages/viral-video/ViralVideoPage.tsx

@@ -1,4 +1,5 @@
 import React, { useCallback, useEffect, useRef, useState } from "react"
+import axios from "axios"
 import {
   PlusOutlined,
   CloseOutlined,
@@ -46,6 +47,7 @@ import {
   analyzeViralImages,
   generateViralCopy,
   confirmViralCopy,
+  estimateViralVideoCredits,
 } from "@/api/viral-video"
 import { useViralVideoPolling } from "./hooks/useViralVideoPolling"
 import CloneModal from "@/components/voice/CloneModal"
@@ -123,6 +125,9 @@ type TabTask = {
   videoModel: string
   quality: string
   upscale: string
+  // 积分预估
+  estimatedCredits: number | null // null=加载中/未发起
+  estimatedCreditsError: boolean // true=接口失败显示 --
   // UI 状态
   uiStep: UIStep
   imageAnalysis: ImageAnalysisResult | null
@@ -395,6 +400,8 @@ const emptyTask = (id: string, title: string): TabTask => ({
   videoModel: "seedance-2.5",
   quality: "480p",
   upscale: "default",
+  estimatedCredits: null,
+  estimatedCreditsError: false,
   uiStep: "step1_upload",
   imageAnalysis: null,
   storyboard: null,
@@ -565,6 +572,50 @@ const ViralVideoPage: React.FC = () => {
   )
   useViralVideoPolling(task.jobId, onPollUpdate)
 
+  /* ── 积分动态预估：STEP2文案生成完成后首次调用；STEP3参数变化时防抖300ms刷新 ── */
+  const creditsTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null)
+  const creditsAbortRef = useRef<number>(0)
+  useEffect(() => {
+    const creditsReady =
+      task.uiStep === "step2_copy_ready" ||
+      task.uiStep === "step3_ready" ||
+      task.uiStep === "step3_generating" ||
+      task.uiStep === "step3_done" ||
+      task.uiStep === "failed"
+    if (!creditsReady) {
+      // 未到可预估阶段：清空状态
+      if (task.estimatedCredits !== null || task.estimatedCreditsError) {
+        setTask({ estimatedCredits: null, estimatedCreditsError: false })
+      }
+      return
+    }
+    // 防抖 300ms
+    if (creditsTimerRef.current) clearTimeout(creditsTimerRef.current)
+    const seq = ++creditsAbortRef.current
+    creditsTimerRef.current = setTimeout(async () => {
+      try {
+        const res = await estimateViralVideoCredits({
+          video_model: task.videoModel,
+          resolution: task.quality,
+          video_ratio: task.videoRatio,
+          duration: task.duration,
+        })
+        if (seq !== creditsAbortRef.current) return
+        setTask({
+          estimatedCredits: res.estimated_credits,
+          estimatedCreditsError: false,
+        })
+      } catch {
+        if (seq !== creditsAbortRef.current) return
+        setTask({ estimatedCredits: null, estimatedCreditsError: true })
+      }
+    }, 300)
+    return () => {
+      if (creditsTimerRef.current) clearTimeout(creditsTimerRef.current)
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [task.videoModel, task.quality, task.videoRatio, task.duration, task.uiStep])
+
   /* ── OSS 上传 ── */
   const uploadFile = useCallback(
     async (file: File, kind: "image" | "video" | "voice", onProgress?: (pct: number) => void) => {
@@ -947,8 +998,21 @@ const ViralVideoPage: React.FC = () => {
       setTask({ job, jobId: job.id })
       message.success("视频已提交生成，预计 1-3 分钟…")
     } catch (err: unknown) {
-      message.error(err instanceof Error ? err.message : "提交失败")
-      setTask({ uiStep: "failed", videoError: err instanceof Error ? err.message : "提交失败" })
+      // 402 Payment Required → 积分不足
+      if (axios.isAxiosError(err) && err.response?.status === 402) {
+        const detail =
+          (err.response.data as { detail?: string; message?: string; msg?: string } | undefined)
+            ?.detail ||
+          (err.response.data as { detail?: string; message?: string; msg?: string } | undefined)
+            ?.message ||
+          "积分不足，请充值"
+        message.error(detail)
+        setTask({ uiStep: "step3_ready", videoError: detail })
+        return
+      }
+      const msg = err instanceof Error ? err.message : "提交失败"
+      message.error(msg)
+      setTask({ uiStep: "failed", videoError: msg })
     }
   }
 
@@ -2031,13 +2095,21 @@ const ViralVideoPage: React.FC = () => {
             </div>
           </div>
 
-          <div className="vv-credits">
-            <span>
-              <SoundOutlined style={{ marginRight: 4 }} />
-              预计消耗
-            </span>
-            <strong>50 积分</strong>
-          </div>
+          {step3Enabled && (
+            <div className="vv-credits">
+              <span>
+                <SoundOutlined style={{ marginRight: 4 }} />
+                预计消耗
+              </span>
+              <strong>
+                {task.estimatedCreditsError
+                  ? "-- 积分"
+                  : task.estimatedCredits === null
+                    ? "… 积分"
+                    : `${task.estimatedCredits} 积分`}
+              </strong>
+            </div>
+          )}
 
           {/* 视频预览区 */}
           <div className="vv-section">