feat(video-from-script): 区分视频生成超时与任务失败，保留 taskId 支持恢复

核心改动：将超时与任务失败明确区分，超时场景保留 taskId 和 pending 状态，
等待下次恢复，避免重复计费；仅 API 明确返回 failed 时才清理 taskId 并重试。

- phase-videos.js: 恢复失败分超时/失败处理，超时保留 taskId 置 pending
- phase-videos.js: 轮询结果超时也保留 taskId 存 pending
- video-poll-utils.js: 增加 isTaskFailed 判断；超时禁止创建新任务
- video-poll-utils.js: 提升轮询重试次数至 5 次以允许超时等待

.claude/skills/video-from-script/scripts/lib/video-poll-utils.js

@@ -2,7 +2,9 @@
  * 共享视频轮询重试工具
  *
  * 提供 pollWithRetry 工厂函数，供 kling/veo/grok 三个视频生成器共用。
- * 两层重试：轮询级（同一 taskId，处理网络瞬断）→ 任务级（创建新 task + 优化提示词）
+ * 两层重试：轮询级（同一 taskId，处理网络瞬断/超时）→ 任务级（仅 API 明确返回 failed 才创建新 task）
+ *
+ * 铁律：超时 ≠ 失败。超时说明服务端还在跑，创建新任务会重复计费。
  */
 
 const path = require('path')
@@ -10,9 +12,11 @@ const fs = require('fs')
 const https = require('https')
 const http = require('http')
 
-const TRANSIENT_RE = /timeout|ECONNRESET|ETIMEDOUT|network|socket/i
+const TRANSIENT_RE = /timeout|ECONNRESET|ETIMEDOUT|network|socket|超时|processing|pending/i
 
-const POLL_RETRIES = 2      // 同一 task 轮询重试次数
+const TASK_FAILED_RE = /\bfailed\b|失败/i
+
+const POLL_RETRIES = 5      // 同一 task 轮询重试次数（含超时等待）
 const POLL_RETRY_DELAY = 5000  // 轮询重试间隔 ms
 const TASK_RETRY_DELAY = 5000  // 任务级重试间隔 ms
 
@@ -20,6 +24,10 @@ function isTransientError(err) {
   return TRANSIENT_RE.test(err.message || '')
 }
 
+function isTaskFailed(err) {
+  return TASK_FAILED_RE.test(err.message || '')
+}
+
 async function download(url, outputPath) {
   const protocol = url.startsWith('https') ? https : http
   return new Promise((resolve, reject) => {
@@ -57,9 +65,16 @@ function makePollWithRetry({ Api, suffix, duration, maxRetries = 3, optimizeProm
     let currentTaskId = taskId
     let currentPrompt = prompt
     let lastError = null
+    let lastErrorWasTaskFailure = false
 
     for (let attempt = 0; attempt <= maxRetries; attempt++) {
       if (attempt > 0) {
+        // 只有 API 明确返回 failed 才创建新任务。超时/网络问题禁止创建新任务（原任务仍在服务端运行，重复计费）
+        if (!lastErrorWasTaskFailure) {
+          const err = new Error(`视频生成超时，放弃等待: ${lastError}`)
+          err.isTaskFailure = false
+          throw err
+        }
         if (optimizePrompt) {
           currentPrompt = optimizePrompt(prompt, lastError, attempt)
         }
@@ -89,8 +104,10 @@ function makePollWithRetry({ Api, suffix, duration, maxRetries = 3, optimizeProm
           }
         } catch (err) {
           lastError = err.message
+          lastErrorWasTaskFailure = isTaskFailed(err)
           if (isTransientError(err) && pollAttempt < POLL_RETRIES) {
-            console.log(`   ⚠ 轮询瞬断 (${pollAttempt + 1}/${POLL_RETRIES}): ${err.message.slice(0, 60)}`)
+            const tag = isTaskFailed(err) ? '失败' : '超时/瞬断'
+            console.log(`   ⚠ 轮询${tag} (${pollAttempt + 1}/${POLL_RETRIES}): ${err.message.slice(0, 60)}`)
             await new Promise(r => setTimeout(r, POLL_RETRY_DELAY))
             continue
           }
@@ -98,13 +115,15 @@ function makePollWithRetry({ Api, suffix, duration, maxRetries = 3, optimizeProm
         }
       }
 
-      if (attempt < maxRetries) {
+      if (attempt < maxRetries && lastErrorWasTaskFailure) {
         await new Promise(r => setTimeout(r, TASK_RETRY_DELAY))
       }
     }
 
-    throw new Error(`重试 ${maxRetries} 次后仍失败: ${lastError}`)
+    const finalErr = new Error(`重试 ${maxRetries} 次后仍失败: ${lastError}`)
+    finalErr.isTaskFailure = true
+    throw finalErr
   }
 }
 
-module.exports = { makePollWithRetry, POLL_RETRIES, POLL_RETRY_DELAY, TASK_RETRY_DELAY }
+module.exports = { makePollWithRetry, isTaskFailed, POLL_RETRIES, POLL_RETRY_DELAY, TASK_RETRY_DELAY }