sentence-transformers safetensors mpnet sentence-similarity feature-extraction dataset_size:10K<n<100K loss:CosineSimilarityLoss arxiv:1908.10084 base_model:sentence-transformers/all-mpnet-base-v2 base_model:finetune:sentence-transformers/all-mpnet-base-v2 autotrain_compatible endpoints_compatible region:us