Add a verify-spa job to the release workflow that rebuilds the SPA
and fails if committed assets are stale, and add the same check to
bin/dev/release.sh so tagging fails before anything is pushed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Add prerelease-aware release automation and keep default install and upgrade
paths pinned to the latest stable tag unless an explicit prerelease version is
requested.