Cover the uncovered branches in the image release script (redirect
handler, policy-read credential and size bounds, count and shape
rejections, EOF manifest scan) and in the Harbor immutability helper
(scope-failure verification, absent robot duration, stale-read retries,
created-rule ID binding, bounded startup retries). Exclude the
__main__ guard like the sibling release script.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
