feat: support commit hash in package version

[ooooo-create]

What does this PR do ?

Adds commit hash into the package version metadata so built wheels/tarballs encode the exact git revision.

1. uv sync
   

2. uv build
   

3. uv run python -c "import nemo_automodel; print(nemo_automodel.__version__); print(nemo_automodel.__git_version__)"
   

Changelog

• build_backend.py:9-107: new custom build backend that gathers git branch/tag/hash, writes - nemo_automodel/_version.py, and appends the hash to version unless on a release branch or tag; exports git_version.
• __init__.py:16-25: re-exports git_version alongside version and package_name.
• package_info.py:15-16: switches to importing version and git_version from the generated _version.py.
• pyproject.toml:15-33: configures the custom build backend and points the dynamic version source to nemo_automodel._version.version.
• .gitignore:162-164: ignores the generated nemo_automodel/_version.py.
• version.txt:1: sets the base package version to 0.2.0.

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Additional Information

• Related to CI: version+commit #691

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[Copilot]

Pull request overview

This PR implements commit hash tracking in package versions to enable better traceability of installed packages. The implementation uses a custom build backend that generates version metadata from git information at build time.

Key Changes:

• Introduces a custom build backend (build_backend.py) that wraps setuptools and generates _version.py with git metadata during builds
• Adds version.txt as the single source of truth for the base package version (0.2.0)
• Exports __git_version__ alongside __version__ for runtime inspection of the exact commit

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
build_backend.py	New custom build backend that generates _version.py with git commit hash, branch, and tag information; wraps setuptools build_meta functions
version.txt	New file containing the base package version (0.2.0)
pyproject.toml	Configures custom build backend and updates dynamic version source to use generated _version.py
nemo_automodel/package_info.py	Replaces hardcoded version constants with imports from generated _version.py
nemo_automodel/init.py	Adds git_version to package exports
.gitignore	Excludes generated _version.py from version control
MANIFEST.in	Includes build_backend.py in source distributions

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[akoumpa]

/ok to test 65eb4a1

[akoumpa]

Thanks a lot for the contribution @ooooo-create ,

I want to move this file out of the top-of-tree. Right now I don't see a directory that's 100% suitable, but perhaps the closest would be test/? @thomasdhc please opine on the matter.