* Add score_answer method to word_ladder
* add unit test for WordLadderDataset::score_answer()
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Co-authored-by: Andreas Koepf <andreas.koepf@provisio.com>
- Added extensive test coverage for word ladder configuration validation
- Implemented tests for neighbor computation, path finding, and graph caching
- Included performance and edge case tests
- Verified solution optimality and path generation logic
- Added tests for word set loading and pair generation