Feature/model attr access

[Mateasek]

Added property access (readonly) to the line and lineshape attributes of emission models, related to #294 . This should allow fully browsing plasma emission models to verify what models were used in observation. This is good for taking logs and result serialisation.

[Copilot]

Pull Request Overview

This PR adds readonly property access to line and lineshape attributes of plasma emission models to enable better introspection and logging capabilities. The changes expose internal model attributes through public properties, allowing users to browse and verify what models were used in observations.

• Added property accessors for line and lineshape attributes across emission model classes
• Updated documentation to include the newly accessible attributes as :ivar entries
• Added changelog entry documenting the API enhancement

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
cherab/core/model/plasma/total_radiated_power.pyx	Added property accessors for element and charge attributes
cherab/core/model/plasma/thermal_cx.pyx	Added property accessors for line and lineshape attributes
cherab/core/model/plasma/recombination.pyx	Added property accessors for line and lineshape attributes
cherab/core/model/plasma/impact_excitation.pyx	Added property accessors for line and lineshape attributes
cherab/core/atomic/line.pyx	Updated documentation to include attribute descriptions as :ivar entries
CHANGELOG.md	Added entry documenting the new emission model attribute access feature

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[jacklovell]

This looks fine to me. Can you add some simple unit tests to check these attribute accesses? That'll guard against regressions in the future. Then I'm happy to merge.

[Mateasek]

Thanks for the review @jacklovell

I added tests for plasma models, but the problem is tests fail because the atomic data are not available. There are two options:

1. I remove the tests which require atomic data, which are most of them
2. Atomic data are obtained before tests are initiated, but I have no idea if it is a good idea or even possible

[jacklovell]

Add some mock atomic data: doesn't have to be physically meaningful but just the bare minimum for the tests.

[Mateasek]

good idea @jacklovell

[Mateasek]

I patched the file reading, the tests now pass. I think this is ready to go @jacklovell