Add PyPI publish workflow for alchemize-ai

[twiecki]

Summary

Adds a GitHub Actions workflow to publish this package to PyPI via Trusted Publishing (OIDC), plus the pyproject + README changes required for the distribution name.

Changes

• pyproject.toml: renamed [project] name from alchemize to alchemize-ai. The PyPI distribution name is alchemize-ai because the alchemize name was already taken on PyPI by an abandoned package. The Python import name stays alchemize — users still do from alchemize import ... and the CLI is still alchemize. The hatchling package discovery (packages = ["alchemize"]) is unchanged.
• .github/workflows/workflow.yml: new workflow that triggers on v* tag push or workflow_dispatch. It builds wheel + sdist with python -m build and publishes via pypa/gh-action-pypi-publish@release/v1. Uses the pypi environment and id-token: write permission for Trusted Publishing — no API tokens.
• README.md: install instructions now show pip install alchemize-ai, with a callout that the import name is still alchemize.

Releasing

1. Bump version in pyproject.toml.
2. Tag and push:

   git tag v0.1.0
   git push origin v0.1.0

3. The workflow builds and publishes automatically (can also be kicked off manually via workflow_dispatch).

Test plan

• Merge and confirm workflow appears under Actions
• Tag a test release (e.g. v0.1.0) and verify Trusted Publishing completes successfully
• Confirm pip install alchemize-ai works and from alchemize import compile_model imports cleanly