fix(xiaohongshu): detect current draft save success

[Astro-Han]

Description

Fix xiaohongshu/publish --draft for the current creator-center UI.

The current UI shows 保存成功 after a successful draft save while staying on /publish/publish?...target=image. The adapter did not treat that as success, so it returned a warning even though the draft was saved.

This change:

• makes success detection mode-specific
• accepts 保存成功 for draft saves
• keeps publish-mode success detection unchanged
• adds regression coverage for both the draft case and the publish-mode guard

Related issue:
#1047

Type of Change

• 🐛 Bug fix
• ✨ New feature
• 🌐 New site adapter
• 📝 Documentation
• ♻️ Refactor
• 🔧 CI / build / tooling

Checklist

• I ran the checks relevant to this PR
• I updated tests or docs if needed
• I included output or screenshots when useful

Documentation (if adding/modifying an adapter)

• Added doc page under docs/adapters/ (if new adapter)
• Updated docs/adapters/index.md table (if new adapter)
• Updated sidebar in docs/.vitepress/config.mts (if new adapter)
• Updated README.md / README.zh-CN.md when command discoverability changed
• Used positional args for the command's primary subject unless a named flag is clearly better
• Normalized expected adapter failures to CliError subclasses instead of raw Error

Screenshots / Output

• npx tsc --noEmit
  • exit code 0
• npx vitest run clis/xiaohongshu/publish.test.js clis/xiaohongshu/navigation.test.js
  • 2 files passed, 22 tests passed
• Live repro:
  • node dist/src/main.js xiaohongshu publish --title 'T8' 'draft body t8' --images /tmp/opencli-xhs-repro.loZBiY/repro.png --draft
  • Result:

    - status: ✅ 暂存成功
      detail: '"T8" · 1张图片 · 保存成功'