Voidworks 0.5.33 - Focused preview saves

Ship saves now refresh purchase previews only for the maps you saved, plus any preview that is missing. Other ships keep their committed images and metadata, even if someone changed their maps without regenerating previews, so those ships no longer show up in unrelated diffs.

When other ships' previews are out of date, the preview status says how many were left alone. Help > Ship Purchase Previews > Refresh outdated previews brings every ship up to date on purpose, so the results can be committed separately.

Beta and Stable are now compared during update checks. Beta users are offered the newer Stable release, as an optional switch that never installs automatically, when Stable is ahead of every beta. Stable users who pick the Beta channel are warned instead of being offered an older beta.

Validation: full bundled test suite, including new tests for saves that keep other ships' outdated previews and for Beta falling behind Stable.

Includes all previous stable features.