fix: remove setup-node cache to avoid pnpm lockfile v9 incompatibility

- Disabled setup-node cache parameter that was causing pnpm store path errors
- The pnpm-lock.yaml uses lockfileVersion 9.0 which is incompatible with setup-node cache
- Manual 'Restore cache' step already handles Next.js build cache
- This resolves: ERROR packages field missing or empty

Author: abr4xas

.github/workflows/nextjs.yml

@@ -56,7 +56,6 @@ jobs:
         uses: actions/setup-node@v4
         with:
           node-version: "20"
-          cache: ${{ steps.detect-package-manager.outputs.manager }}
       - name: Setup Pages
         uses: actions/configure-pages@v5
         with: