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/phase-videos.js

@@ -44,7 +44,7 @@ async function phaseVideos(manifest, manifestPath, options) {
     console.log()
   }
 
-  // 已有视频（本地或 OSS）且状态为 done 的跳过，其余清理后重新生成
+  // 已有视频（本地或 OSS）且状态为 done 的跳过，其余清理视频引用但保留 taskId 供恢复
   const items = []
   for (const it of videoCandidates) {
     if (it.video || it.videoUrl) {
@@ -52,7 +52,6 @@ async function phaseVideos(manifest, manifestPath, options) {
       delete it.video
       delete it.videoUrl
       delete it.videoDuration
-      delete it.videoTaskId
     }
     items.push(it)
   }
@@ -107,9 +106,15 @@ async function phaseVideos(manifest, manifestPath, options) {
             log('videos', `  item ${item.id} 恢复成功`)
           }
         } catch (err) {
-          log('videos', `  item ${item.id} 恢复失败: ${err.message}，将重新提交`)
-          delete item.videoTaskId
-          needSubmit.push(item)
+          const isFail = err.isTaskFailure === true
+          if (isFail) {
+            log('videos', `  item ${item.id} 恢复失败（任务失败）: ${err.message}，将重新提交`)
+            delete item.videoTaskId
+            needSubmit.push(item)
+          } else {
+            log('videos', `  item ${item.id} 恢复超时（保留 taskId 下次重试）: ${err.message}`)
+            item.status = 'pending'
+          }
         }
       })
     )
@@ -172,25 +177,32 @@ async function phaseVideos(manifest, manifestPath, options) {
         })
         return { item, result, ok: true }
       } catch (err) {
-        return { item, error: err.message, ok: false }
+        return { item, error: err.message, ok: false, isTaskFailure: err.isTaskFailure === true }
       }
     })
   )
 
   for (const r of pollResults) {
-    const val = r.status === 'fulfilled' ? r.value : { ok: false, error: r.reason?.message }
+    const val = r.status === 'fulfilled'
+      ? r.value
+      : { ok: false, error: r.reason?.message || String(r.reason), isTaskFailure: r.reason?.isTaskFailure === true }
     if (val.ok && val.result.file) {
       val.item.video = path.relative(dir, val.result.file).replace(/\\/g, '/')
       val.item.videoDuration = val.result.duration
       val.item.status = 'done'
       delete val.item.videoTaskId
     } else if (val.item) {
-      val.item.status = 'failed'
-      val.item.error = val.error || '视频生成未返回文件'
-      delete val.item.videoTaskId
+      if (val.isTaskFailure) {
+        val.item.status = 'failed'
+        val.item.error = val.error || '视频生成未返回文件'
+        delete val.item.videoTaskId
+      } else {
+        log('videos', `  item ${val.item.id} 生成超时（保留 taskId 待恢复）: ${val.error}`)
+        val.item.status = 'pending'
+      }
     }
+    saveManifest(manifestPath, manifest)
   }
-  saveManifest(manifestPath, manifest)
 
   // 上传视频到 OSS
   const { uploadFile } = require('../oss-upload')