Clean up codebase and prepare as template

Remove unused files and code:
- Delete test/debug endpoints (test.get.ts, public.get.ts, user.get.ts, debug-config backup)
- Remove unused OAuth wrapper (oauth-authentik.ts)
- Clean up debug console.log statements
- Simplify code comments

Fix TypeScript errors:
- Add @types/node dependency
- Create index.d.ts with User interface extension
- Fix UButton color props (red→error, gray→neutral)
- Add type assertions in protected.get.ts

Update documentation:
- Enhance README.md as template documentation
- Update SETUP.md with correct API routes (/api/auth/* instead of /auth/*)
- Add NUXT_OAUTH_AUTHENTIK_SERVER_URL_INTERNAL documentation
- Update endpoint documentation

This commit prepares the repository to be used as a template for future Nuxt 4 + Authentik OAuth projects.

nuxt4-app/server/api/protected.get.ts

@@ -1,21 +1,16 @@
 /**
  * Protected API Endpoint
- * Ruta: /api/protected
- *
- * Endpoint protegido que requiere autenticación
- * Retorna datos sensibles solo para usuarios autenticados
+ * Requires authentication - returns user-specific data
  */
 export default defineEventHandler(async (event) => {
-  // Verificar autenticación
   const session = await requireUserSession(event)
 
   return {
     message: 'Datos protegidos del usuario',
-    user: session.user.username,
+    user: (session.user as any).username,
     data: {
-      // Aquí puedes añadir datos específicos del usuario
       lotes: [],
-      permissions: session.user.groups || []
+      permissions: (session.user as any).groups || []
     },
     timestamp: new Date().toISOString()
   }