This PR adds a check to both `release_checklist.py` and CI to verify that
`stage0/src/CMakeLists.txt` has the same LEAN_VERSION_MAJOR and
LEAN_VERSION_MINOR as the release tag. The stage0 pre-built compiler stamps
.olean headers with its baked-in version, so a mismatch causes the release
tarball to contain .olean files with the wrong version. This happened in
v4.29.0-rc2 (https://github.com/leanprover/lean4/issues/12681) because the
'begin development cycle for v4.30.0' commit bumped stage0 to 4.30.0 before
the release was cut.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2152eddfb4