fix: uninstall yarn 1.x before corepack prepare and fix corepack indent

npm_install.py

@@ -2173,6 +2173,9 @@ def _build_frontend(src_frontend: Path, dest_frontend: Path):
             # METHOD 1: Corepack (recommended for Yarn 4.x)
             if shutil.which("corepack"):
                 try:
+                    # Uninstall old yarn 1.x to prevent conflicts
+                    subprocess.run(["npm", "uninstall", "-g", "yarn"], check=False, cwd="/tmp")
+                    
                     # Enable corepack
                     subprocess.run(
                         ["corepack", "enable"],