fix: handle hanging yarn binary in _pick_yarn_cmd

npm_install.py

@@ -1991,10 +1991,19 @@ def _build_frontend(src_frontend: Path, dest_frontend: Path):
         # Check yarn in PATH
         yarn_bin = shutil.which("yarn")
         if yarn_bin:
-            result = subprocess.run([yarn_bin, "--version"], capture_output=True, text=True, timeout=5)
+            try:
-            if DEBUG:
+                result = subprocess.run([yarn_bin, "--version"], capture_output=True, text=True, timeout=3)
-                print(f"    debug pick: yarn_bin={yarn_bin}, version={result.stdout.strip()}, major={_get_yarn_major_version(['yarn'])}")
+                if DEBUG:
-            major = _get_yarn_major_version(["yarn"])
+                    print(f"    debug pick: yarn_bin={yarn_bin}, version={result.stdout.strip()}")
+                major = _get_yarn_major_version(["yarn"])
+            except (subprocess.TimeoutExpired, Exception):
+                if DEBUG:
+                    print(f"    debug pick: yarn_bin={yarn_bin} HANGS, removing...")
+                try:
+                    subprocess.run(["rm", "-f", yarn_bin], check=False)
+                    major = None
+                except Exception:
+                    major = None
             if major and major >= 4:
                 return ["yarn"]
             elif major: