Publish to PyPI

[munzzyy]

The README install path is still pip install git+https://github.com/munzzyy/liftmath. The name liftmath was unclaimed on PyPI last I checked.

What this needs: a PyPI account decision on my end, trusted publishing set up from CI, and a release workflow that builds the sdist/wheel and pushes on tag. Not hard, just deliberate - once the name is claimed the install line in the README changes and stays that way.

[munzzyy]

Checked the actual state of this instead of assuming the issue text was still current - looks like this already happened:

• The name's claimed. liftmath's been on PyPI since 1.5.0, currently at 2.3.0 (4 versions actually published: 1.5.0, 2.1.0, 2.2.0, 2.3.0 - more on the gap below).
• release.yml already does trusted publishing (OIDC, no stored token) on release: published, builds the sdist/wheel, runs twine check, installs the built wheel and smoke-tests the CLI before publishing.

One real gap while I was in there: v2.0.0 (the "focus" release) has a GitHub tag and Release but never made it to PyPI, and there's no Action run for it at all - not even a failed one. release.yml already existed on main by the time that release was published, so this isn't just "predates the workflow" (that explains 1.0.0-1.4.0, which really did predate it). Doesn't affect anyone installing today (pip install liftmath always gets 2.3.0), but pip install liftmath==2.0.0 would 404. Not something I can fix after the fact - flagging it since I found it while checking this.

What was actually thin: pyproject.toml had an empty classifiers list, so the PyPI project page had no Python-version/status/license badges. Filled that in plus Changelog/Issues project URLs in 8249071 - twine check passes on both dist artifacts.

No PyPI click left to make for the current release. Leaving this open in case you want to look into the 2.0.0 gap or just close it out.