## Why
Publishing an older stable version should not replace a newer release as the default download or installation target.
## What changed
- Compare stable versions before marking a GitHub release as latest, allowing same-version reruns to finish publication.
- Guard npm `latest` and platform dist-tags, publishing older versions under separate `release-<version>-<tag>` tags.
- Check R2's `latest` channel before updating it or the installer aliases, while allowing same-version reruns to repair interrupted installer updates.
- Reject invalid existing stable release metadata and consolidate GitHub latest and canary checks in `releases.py`.
## Testing
Add regression tests for stable version ordering, same-version reruns, npm package and platform tags, and invalid channel metadata. All 21 tests in `.github/scripts/test_releases.py` pass.
GitOrigin-RevId: e6bad3ee163b279ac1661b9070712a41eedd50ff
## Why
Publishing a hotfix for an older release line or alpha can replace a newer prerelease pointer. Release pointers should advance according to version order.
## What changed
- Share release version validation and numeric comparison across publishing scripts, including alpha hotfix suffixes and alpha, beta, and stable ordering.
- Read the prerelease pointer directly from R2 and update it only for a newer version or missing or invalid version metadata.
- Restrict `latest-alpha-cli` updates to alpha releases with successful R2 and npm publishing, and compare against the branch's Cargo version before advancing it. Allow replacement when the manifest version cannot be parsed or validated.
## Testing
Add 15 passing unit tests covering version validation, older release lines and alphas, numeric hotfix ordering, prerelease precedence, equal versions, and missing or invalid versions.
GitOrigin-RevId: 6bee3906a47f613b662ef2b2224cfcbd1b56650c
andrewgu-oai