CachedGISTEmbedLoss

This release focuses on correctness and performance, rebuilding gradient-cached losses on a shared engine for faster training and fixing several gradient bugs. It also significantly improves inference speed when using `model.compile()`.

This minor release focuses on correctness and robustness, fixing silent scoring bugs related to chat-template truncation and improving stability for hard-negative mining and GIST losses. It also introduces MPS support and restores TSDAE functionality on recent `transformers` versions.