Previously the release job only ran on v* tag pushes, leaving
main-branch builds with no downloadable binaries.
- Release job now also triggers on push to main
- On main: force-moves the 'latest' git tag to the current commit,
then creates/updates a 'latest' pre-release with the built artifacts
- On v* tag: existing versioned release behaviour unchanged
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
