Add custom polars Kurucz reader and test

[lukeshingles]

No description provided.

[Copilot]

Pull request overview

This pull request adds a custom Polars-based Kurucz data reader to replace the dependency on the carsus library. The PR includes significant changes to the data processing pipeline and introduces breaking changes to the Python and pandas version requirements.

Changes:

• Implements a custom GFALL parser using Polars instead of relying on carsus
• Updates minimum Python version from 3.11 to 3.12
• Updates pandas requirement from 2.3.0 to 3.0.0
• Adds Kurucz test data and checksums
• Introduces ARTISATOMIC_TESTMODE environment variable for test isolation

Reviewed changes

Copilot reviewed 9 out of 15 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
artisatomic/readkuruczdata.py	Complete rewrite with custom GFALL parser using polars; replaces carsus dependency
artisatomic/readqubdata.py	Adds test mode support via environment variable
pyproject.toml	Bumps minimum Python to 3.12 and pandas to 3.0.0; removes Python 3.11 classifier
.github/workflows/test.yml	Adds ARTISATOMIC_TESTMODE environment variable; adds kurucz to test matrix; removes QUB rsync step
tests/kurucz/*	Adds new test files, checksums, and configuration
tests/qub/checksums.txt	Updates checksums for co2.txt and co3.txt
atomic-data-kurucz/.gitignore	Updates ignore patterns for new file organization
atomic-data-kurucz/url.txt	Changes URL from gfall/ to gfall/zztar
atomic-data-kurucz/test_sample/zztar/*	Adds compressed test data files
uv.lock	Removes Python 3.11 wheels and updates dependencies

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[Copilot]

Pull request overview

Copilot reviewed 9 out of 15 changed files in this pull request and generated 3 comments.

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