Test job on main green again

Since git calls moved onto threads of their own, the test job on main failed in every run although every test passed: Bun reported one unhandled rejection at the end of the workspace tests. The cause was a test that waited for an expected failure with expect(…).rejects alone, which on GitHub's runner counted as unhandled. The workspace tests now take such failures with a handler of their own; Obeya's own code is unchanged.