Publish stable and nightly package channels

[JordanNanos]

Purpose

Publish stable and nightly ClusterMAX packages from one trusted GitHub Actions workflow.

The current workflow can publish development builds only. A stable 0.2.1 package is required for default pip installation.

What changed

• The publication workflow accepts stable and nightly channels.
• The stable channel uses the version in the source package.
• The nightly channel uses the 0.3.0.devYYYYMMDDNN format.
• The README explains the stable and nightly installation behavior.
• The version test proves that the nightly version is newer than stable 0.2.1.

Effect

• Users: Default installation selects 0.2.1. Installation with --pre selects the newest 0.3.0 development build.
• Operators: A workflow dispatch can select stable or nightly publication.
• Developers: The scheduled workflow continues to select the nightly channel.
• Data and compatibility: Published package data does not change. Python 3.10 or later remains required.

Technical terms

• PyPI: The Python Package Index that hosts installable Python packages.
• pip: The Python package installer.
• --pre: A pip option that permits prerelease versions.
• development build: A prerelease package created from code before the stable 0.3.0 release.
• GitHub Actions: The GitHub automation service that builds and publishes the package.

Validation

• uv run --isolated --with pytest --with packaging python -m pytest -q tests/test_nightly_version.py: Pass. Six tests passed.
• uv run --isolated --with pytest --with pyyaml --with prompt-toolkit python -m pytest -q: Pass. 1,306 tests and 835 subtests passed.
• Local wheel resolver test: Pass. Default selected 0.2.1 and --pre selected 0.3.0.dev2026082801.
• git diff --check: Pass.

Merge plan

• Merge order: None. This PR can merge independently.
• Dependency: The PyPI trusted publisher must permit .github/workflows/python-nightly.yml in SemiAnalysisAI/ClusterMAX with the pypi environment. This dependency is complete.
• Release step: Dispatch the stable channel from master. Approve publication. Then dispatch and approve the nightly channel.

Design decisions for approval

• Approval required: Yes.
• Decision: Use 0.3.0 development versions for nightly packages after stable 0.2.1.
• Options: Use 0.2.2 development versions or 0.3.0 development versions.
• Recommendation: Use 0.3.0 development versions because this is the next planned stable release.
• Approver: JordanNanos approved the 0.3.0 development version before this PR.

Risk and recovery

• Risk: An incorrect channel can publish an unwanted permanent version to PyPI.
• Safeguard: The stable channel uses the source version. The protected environment requires publication approval.
• Rollback: Revert the workflow change. Yank an incorrect PyPI release if publication occurs.

Excluded work

• This PR does not publish a package before merge.
• This PR does not change the source package version from 0.2.1.

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Note

Medium Risk
Wrong channel or version logic can publish an unintended immutable PyPI release; safeguards are channel-specific versioning and the protected pypi environment.

Overview
Renames the GitHub Actions workflow to python-publish and adds a workflow_dispatch channel (stable or nightly, default nightly). Scheduled runs still publish nightlies; operators can manually publish stable from master.

Version selection no longer hardcodes 0.2.1 for every build. Stable uses cmax.__version__ from the repo (still 0.2.1 in this PR). Nightly builds use 0.3.0.devYYYYMMDDNN via NIGHTLY_VERSION: 0.3.0 and the existing nightly script. Concurrency groups are per channel; build checks assert the source tree version while the wheel/CLI report the publication version.

README documents the new nightly prefix and that --pre picks a prerelease newer than stable 0.2.1. Tests fix the script path, expect 0.3.0 in nightly fixtures, and add a check that the nightly string sorts above 0.2.1.

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