fix(plugin): resolve host imports from monorepo shared directories

[lorenzozanee]

Description

Related issue: #2373

This updates monorepo installation to link @jackwener/opencli at the repository root, so helpers in sibling shared directories can resolve the host package exports. Existing per-plugin links remain unchanged.

A regression test covers importing @jackwener/opencli/errors from packages/shared/.

Fixes #2373

Type Change

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

Checklist

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

Documentation (if adding/modifying 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 command's primary subject unless named flag clearly better
• Normalized expected adapter failures CliError subclasses instead raw Error

Screenshots / Output