test_release_script_generates_checksummed_artifacts hard-coded
`dirty == 1`, which only held while the worktree happened to be dirty. The
script derives `dirty` from actual git state and RELEASE_ALLOW_DIRTY is a
permission flag, not a forced value — so the test failed the moment the tree
was clean (all work committed). Compute the expected dirty flag the same way
the script does so the test is deterministic on both clean and dirty trees.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
