🔗 Linked issue

Refs: #1330, #1384 <!-- related PRs/discussions about Nuxt 4 tsconfig detection -->

❓ Type of change

• 📖 Documentation (updates to the documentation, readme or JSdoc annotations)
• 🐞 Bug fix
• 👌 Enhancement
• ✨ New feature
• 🧹 Chore
• ⚠️ Breaking change

📚 Description

Explain
Nuxt 4 defaults to the app/ directory and commonly uses a root tsconfig.json with project references only.
The shadcn-vue CLI validates TS path aliases from tsconfig.json/jsconfig.json, so without explicit compilerOptions.paths, users can hit “No import alias found”.
Also, pointing componentDir at ./components/ui (Nuxt 3 style) can confuse Nuxt 4 users whose components live under app/components/ui.

What this PR changes

1. Add a tsconfig.json (aliases) section (before nuxt.config.ts) showing explicit compilerOptions.paths:
   • Keep @/* and ~/* mapped to project root.
   • Map @/components/* → ./app/components/* (Nuxt 4).
2. In Configure nuxt.config.ts, set
   shadcn.componentDir = './app/components/ui' for Nuxt 4.
3. Doc note about ordering: run the CLI before nuxi prepare (or mention mkdir -p app/components/ui) to avoid the “Component directory does not exist …/components/ui” warning.
4. Keep Nuxt 3 instructions intact.

Why
Ensures init/add pass alias validation and avoids confusing warnings for Nuxt 4 users.
Forward-compatible with ongoing work to auto-detect tsconfig for Nuxt (#1330, #1384).

Tested

• Fresh Nuxt 4 app:
  • npx shadcn-vue@latest init ✅
  • npx shadcn-vue@latest add button ✅
  • npx nuxi prepare → no warnings ✅

📸 Screenshots (if appropriate)

N/A (docs-only)

📝 Checklist

• I have linked an issue or discussion. (Refs: #1330, #1384)
• I have updated the documentation accordingly.