[lucasfang]

Purpose

Cutting a release branch does not mean that version has been published. The existing two-version command also promotes the current version to stable, so it cannot advance main safely while the release is still being prepared.

Add --dev-only CURRENT_VERSION NEW_VERSION to update CMake and the documentation development version while preserving versions.json byte for byte. Keep the existing post-release promotion behavior. Use the new mode to advance main from 0.4.0 to 0.5.0 while 0.3.0 remains stable.

Tests

• python3 -m unittest discover -s scripts/releasing/tests -v -k version_tool -k docs_channels: all 11 tests passed. Coverage includes stable/archive preservation, existing label and formatting preservation, dry-run behavior, invalid arguments, and compatibility with the existing promotion modes.
• Ran the new mode against a temporary copy of the current version metadata and verified that both applied version files match its output exactly; versions.json matches HEAD.
• python3 scripts/releasing/bump_version.py --check 0.5.0: passed.
• PYENV_VERSION=3.11.15 pre-commit run --files CMakeLists.txt docs/source/conf.py scripts/releasing/bump_version.py scripts/releasing/tests/test_release_tools.py scripts/releasing/README.md: passed.
• git diff --check: passed.
• C++ builds and tests were not run; the changes concern the Python release tool, its documentation and tests, and version metadata.

API and Format

Adds an optional CLI mode. No C++ public API, storage format, or protocol changes.

Documentation

Document the branch-cut development bump and promoting stable documentation on the release branch after publication, then carrying that version-list update back to main.

Generative AI tooling

Generated-by: OpenAI Codex (GPT-6)