fix: catch TimeoutExpired in parallel runner wait loop

The initial wait loop used proc.wait(timeout=0.5) which could raise
subprocess.TimeoutExpired and crash the runner. Added a try/except and
increased timeout to 5s so the runner polls correctly without crashing.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

scripts/run_molecule_parallel.py

@@ -106,7 +106,10 @@ def cli(pairs: tuple[str, ...]) -> None:
         if not finished_indices:
             # No process finished yet, wait a bit
             for proc in processes:
-                proc.wait(timeout=0.5)
+                try:
+                    proc.wait(timeout=5)
+                except subprocess.TimeoutExpired:
+                    pass
             continue
 
         # Remove finished processes from the list

tests/unit/test_run_molecule_parallel.py

@@ -147,6 +147,40 @@ class TestCli:
             assert result.exit_code == 1
             assert "FAILURE" in result.output
 
+    def test_wait_loop_handles_timeout(self, tmp_path: Path) -> None:
+        from click.testing import CliRunner
+
+        with (
+            patch("scripts.run_molecule_parallel.run_pair") as mock_run_pair,
+            patch("os.killpg") as mock_killpg,
+            patch("os.getpgid") as mock_getpgid,
+        ):
+            mock_getpgid.return_value = 123
+
+            good_proc = MagicMock()
+            good_proc.poll.return_value = None
+            good_proc.wait.side_effect = [
+                subprocess.TimeoutExpired("cmd", 5),
+                None,
+                None,
+            ]
+            bad_proc = MagicMock()
+            bad_proc.poll.side_effect = [None, 1, 1, 1]
+            bad_proc.wait.return_value = None
+            mock_run_pair.side_effect = [bad_proc, good_proc]
+
+            runner = CliRunner()
+            result = runner.invoke(
+                cli,
+                [
+                    "default|ubuntu-2204|img:latest|",
+                    "lifecycle|debian-12|img:deb|",
+                ],
+            )
+            assert result.exit_code == 1
+            assert "FAILURE" in result.output
+            mock_killpg.assert_called()
+
 
 def test_main_module_block() -> None:
     import scripts.run_molecule_parallel as rm