fix(xiaohongshu): require signed note URLs

[Astro-Han]

Description

Require signed Xiaohongshu note URLs for note and comments, while keeping download compatible with signed note URLs or xhslink short links. This removes the stale bare-note-ID flow that was navigating to tokenless note URLs and getting blocked by Xiaohongshu risk control.

Related issue: #994

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

$ npm test
Test Files  197 passed (197)
Tests  1497 passed | 2 skipped (1499)

$ node dist/src/main.js validate
opencli validate: PASS
Checked 557 command(s)
Errors: 0  Warnings: 7

$ node dist/src/main.js xiaohongshu note 69db64f1000000001d01a329 -f json
ok: false
error:
  code: ARGUMENT
  message: xiaohongshu note now requires a full signed URL
  help: Pass a full Xiaohongshu note URL with xsec_token from search results or user/profile context.
  exitCode: 2