feat: 封面生成流水线、执黑先行二号风格扩展、账号配置更新

- 新增 gen-covers 系列脚本（kling/gpt/t2i/batch/direct/final等方案）
- 执黑先行二号添加9种风格提示词目录（梦核/剪纸/水墨/毛毡/硬核线条等）
- 执黑先行添加封面提示词、执黑先行二号更新图片提示词
- product_viral_factory 账号配置扩充并添加 cover_template 参考图
- capcut_assemble/kling-video-generator/oss-upload/poll-utils 细节修复
- CLAUDE.md 更新流程文档

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/skills/video-from-script/scripts/oss-upload.js

@@ -57,12 +57,10 @@ async function uploadFile(filePath, options = {}) {
   const ossPath = `${folder}${basename}`
 
   const stat = fs.statSync(filePath)
-  const opts = stat.size > 50 * 1024 * 1024
-    ? { timeout: 600000 }  // 10min for large files
-    : {}
+  const timeout = stat.size > 50 * 1024 * 1024 ? 600000 : 300000
 
   const stream = fs.createReadStream(filePath)
-  await client.putStream(ossPath, stream, { ...opts, contentLength: stat.size })
+  await client.putStream(ossPath, stream, { timeout, contentLength: stat.size })
 
   const expires = config.ossExpires || 31536000
   const url = client.signatureUrl(ossPath, { expires })