clean up discmodel basics

[michael-petersen]

This pull request introduces several improvements to the discmodel package, focusing on reproducibility, improved test coverage, and code cleanup. The most significant change is the refactoring of random number generation in DiscGalaxy to use an instance-specific random seed, ensuring reproducible results without affecting global random state. Additional enhancements include more robust error handling, expanded tests for optional dependencies, and various code and configuration cleanups.

[Copilot]

Pull request overview

This PR cleans up and hardens the discmodel package with a focus on reproducibility and more robust handling of optional dependencies, while also simplifying packaging/test configuration.

Changes:

• Refactors DiscGalaxy initialization to use an instance-provided seed instead of reseeding NumPy’s global RNG.
• Expands/adjusts tests around optional dependencies (flex, lintsampler) and adds a regression test to ensure initialization doesn’t reset global RNG state.
• Packaging/config cleanup: simplified setup.py, adjusted pytest.ini import path behavior, and improved version fallback in __init__.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
tests/test_optional_imports.py	Adds direct tests for optional import check helpers (but current monkeypatching logic introduces recursion).
tests/test_discmodel.py	Adds pytest usage, validates phasespace init N, adds RNG non-interference test, and skips optional-dependency tests when deps are missing.
src/discmodel/discmodel.py	Adds seed parameter and uses an instance RNG for initial sampling; improves error handling in make_expansion; removes dead/commented code.
src/discmodel/init.py	Makes __version__ robust when package metadata isn’t available (e.g., source checkout).
setup.py	Switches to declarative setuptools configuration by calling setup() with no args.
pytest.ini	Ensures src is on pythonpath for tests.
pyproject.toml	Updates the project homepage URL.

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.