feat(video-from-script): 视频生成阶段增加重复任务检测与原子状态标记

在视频生成流水线中添加两项关键改进：

1. 在 `cmdNext` 中提前将条目状态标记为 `processing` 并持久化，防止同一行被多个并行进程重复取出处理
2. 在 `phaseVideos` 中增加磁盘兜底检测：对无 `video` 字段的条目，根据 `id` 扫描本地视频目录，若发现已有视频文件则恢复引用并跳过生成
3. 优化状态过滤逻辑：`done` 状态且已有视频文件的条目明确跳过并输出原因，减少冗余日志

.claude/skills/video-from-script/scripts/batch-pipeline.js

@@ -304,6 +304,11 @@ function cmdNext(args) {
     return
   }
 
+  // 原子标记为 processing，防止同一行被重复取出
+  item.status = 'processing'
+  batch.stats = calcStats(batch.items)
+  writeJson(manifestPath, batch)
+
   const result = {
     done: false,
     row: item.row,

.claude/skills/video-from-script/scripts/lib/phase-videos.js

@@ -43,6 +43,8 @@ async function phaseVideos(manifest, manifestPath, options) {
   const videoCandidates = manifest.items.filter(it => {
     if (it.confirmed === false) return false
     if (!it.url || !it.videoPrompt) return false
+    // 已有视频（本地文件或远程 URL）且状态为 done → 跳过，避免重复生成
+    if (it.status === 'done' && (it.video || it.videoUrl)) return false
     return ['done', 'pending', 'failed'].includes(it.status)
   })
 
@@ -54,7 +56,9 @@ async function phaseVideos(manifest, manifestPath, options) {
       if (it.confirmed === false) reasons.push("confirmed=false")
       if (!it.url) reasons.push("缺少 url（图片未上传）")
       if (!it.videoPrompt) reasons.push("缺少 videoPrompt")
-      if (it.confirmed !== false && it.url && it.videoPrompt && !["done","pending","failed"].includes(it.status)) {
+      if (it.status === 'done' && (it.video || it.videoUrl)) {
+        reasons.push("视频已生成，已跳过")
+      } else if (!["done","pending","failed"].includes(it.status)) {
         reasons.push("status=" + (it.status || "undefined") + "（不在 done/pending/failed 中）")
       }
       console.log("   - item", it.id || manifest.items.indexOf(it), ":", reasons.length > 0 ? reasons.join(", ") : "已满足全部条件（不应在此）")
@@ -66,6 +70,20 @@ async function phaseVideos(manifest, manifestPath, options) {
 
   const items = []
   for (const it of videoCandidates) {
+    // 磁盘兜底：本地视频文件已存在则恢复引用并跳过
+    if (!it.video && it.id) {
+      const fs = require('fs')
+      const existingVideos = fs.readdirSync(videosDir).filter(f =>
+        f.includes('_item' + it.id + '_') || f.includes('_item' + it.id + '.')
+      )
+      if (existingVideos.length > 0) {
+        it.video = 'videos/' + existingVideos[existingVideos.length - 1]
+        it.status = 'done'
+        delete it.videoTaskId
+        log('videos', `  item ${it.id} 发现已有视频文件 ${it.video}，跳过生成`)
+        continue
+      }
+    }
     if (it.video || it.videoUrl) {
       if (it.status === 'done') continue
       delete it.video