[JesperDramsch]

Everything 0.3.0 needs apart from the release itself. Five commits:

1. build:
   • requires-python >=3.11, tensorflow>=2.15, numpy.
   • Drops scipy and scikit-learn, which nothing imports.
   • Python classifiers become 3.11 to 3.13.
   • The README becomes the PyPI description (readme = "README.md").
   • Removes requirements.txt, which duplicated the dependencies and is no longer used.
2. ci: trusted publishing.
   • publish.yml uses the PyPI environment and id-token: write, matching the trusted publisher on pypi.org, instead of the 2022 API token.
   • It now runs only when a GitHub release is published; workflow_dispatch is gone, so no branch can be uploaded by hand.
3. ci: package check. A new job builds the sdist and wheel, runs twine check --strict, and installs the wheel with current pip. 0.2.3's invalid metadata is what makes pip 24.1 and later skip it; this job would have caught that.
4. docs: CITATION.cff. It now validates against CFF 1.2.0; before, cffconvert rejected it.
   • The article details move into preferred-citation (journal, volume, article number and year, all matching Crossref).
   • ORCIDs become URLs, and DOIs lose the resolver prefix.
5. docs: README.
   • The interim Keras 3 note is replaced by the current status, with no version numbers that would go stale.
   • Requirements are updated, and the old "very much in Alpha" sentences are removed.
   • Components that still fail are listed, each checked today on Keras 3 (TensorFlow 2.21) and Keras 2 (TensorFlow 2.15.1). norm.LayerNormalization works on both now, so it isn't listed.

Verification

• CI on this PR: all green.
  • Keras 3 on Python 3.11 to 3.13 and both Keras 2 jobs: 18 passed each.
  • lint and pre-commit.ci pass.
  • package: twine PASSED for wheel and sdist, and pip 26.2.1 installed the wheel with its dependencies.
• Local: validate-pyproject and cffconvert --validate pass; 18 tests pass on Keras 3; pre-commit hooks clean.

After merging

1. I draft the v0.3.0 release; you click Publish. The tag gives version 0.3.0 through setuptools-scm, and the publish job uploads it.
2. Once 0.3.0 is on PyPI, the repository secrets PYPI_API_TOKEN, PYPI_USERNAME and PYPI_PASSWORD can be deleted. Password uploads have been refused by PyPI since 2023.

Still open for the classifier: it says Development Status :: 3 - Alpha. I left it, since several modules don't work; change it if you see it differently.