Add unit tests (92% coverage) and fix E5/E6 bugs from issue #352

[GernotMaier]

• Add 12 new test files covering all production modules
• Raise overall test coverage to 92%
• Fix E5: process_file_chunked uses features_tmva_style when tmva_style=True
• Fix E6: configure_training no longer raises AttributeError when energy_bins_log10_tev is absent (fallback changed from [] to {})
• Add regression tests for both bugs
• Add diagnostics/ to .gitignore

[Copilot]

Pull request overview

This PR aims to substantially increase automated test coverage across Eventdisplay-ML while addressing two reported regressions (E5/E6 from issue #352) in the classification application/training configuration paths.

Changes:

• Add a broad suite of new unit tests spanning most production modules (utils, config, models, data_processing, evaluate, diagnostic_utils, geomag, and optimization helpers).
• Fix E5 by adding TMVA-style branch selection logic to models.process_file_chunked for classification when tmva_style=True.
• Fix E6 by changing the energy_bins_log10_tev fallback in configure_training to avoid an AttributeError when the key is absent.

Reviewed changes

Copilot reviewed 16 out of 17 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/eventdisplay_ml/models.py	Adds TMVA-style feature branch selection in process_file_chunked for classification.
src/eventdisplay_ml/config.py	Adjusts fallback default for missing energy_bins_log10_tev when building classification pre-cuts.
tests/test_config.py	Adds coverage for configure_training / configure_apply, including an E6 regression test.
tests/test_models_helpers.py	Adds unit tests for model loading/applying helpers, including an E5 regression test.
tests/test_utils.py	Adds tests for utility helpers (path resolution, parsing, parameter loading, naming).
tests/test_hyper_parameters.py	Adds tests for hyperparameter dispatch and pre-cut construction.
tests/test_features.py	Adds tests for feature lists, exclusions, and TMVA-style feature variants.
tests/test_geomag.py	Adds tests for geomagnetic angle calculation correctness and error handling.
tests/test_data_helpers.py	Adds unit tests for pure helper functions used in data flattening/preprocessing.
tests/test_data_processing_remaining.py	Covers remaining data_processing branches (aliases, optional cols, TMVA-style load path).
tests/test_evaluate_helpers.py	Adds tests for evaluate.py helper functions and logging behavior.
tests/test_evaluate_remaining.py	Covers remaining evaluate.py branches (zenith grouping, SHAP-per-energy paths).
tests/test_diagnostic_utils.py	Adds tests for diagnostic metric computations.
tests/test_diagnostic_utils_full.py	Adds tests for cached metrics/importance loading and residual diagnostics utilities.
tests/test_optimize_helpers.py	Adds tests for helper functions used by scripts/optimize_classification.py.
docs/changes/352.bugfix.md	Towncrier fragment documenting the E5/E6 fixes.
.gitignore	Ignores diagnostics/ directory.