Fix Windows test compatibility with proper cross-platform temp path assertion

Fix the final Windows test failure in test_get_result_success by using
proper cross-platform temporary directory detection.

Issue: Windows temp paths like 'C:\Users\RUNNER~1\AppData\Local\Temp\tmpmv3bwcx3'
don't match Unix-style patterns like endswith('tmp') or contain '/tmp'.

Solution: Use tempfile.gettempdir() to get the actual system temp directory
and verify the path starts with that directory, making the test truly
cross-platform compatible.

Before:
assert call_args[1].endswith("tmp") or "/tmp" in call_args[1]

After:
temp_dir = tempfile.gettempdir()
assert call_args[1].startswith(temp_dir)

This ensures 120/120 tests pass on ALL platforms: Linux, macOS, Windows.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: jeremymanning

tests/test_executor.py

@@ -465,7 +465,11 @@ def mock_get(remote_path, local_path):
         mock_sftp.get.assert_called_once()
         call_args = mock_sftp.get.call_args[0]
         assert call_args[0] == "/tmp/test_job/result.pkl"  # remote path
-        assert call_args[1].endswith("tmp") or "/tmp" in call_args[1]  # local temp path
+        # Verify local path is a temporary file (cross-platform)
+        import tempfile
+
+        temp_dir = tempfile.gettempdir()
+        assert call_args[1].startswith(temp_dir)  # local temp path
 
     def test_cancel_job_slurm(self, executor):
         """Test canceling SLURM job."""