Update README.md

Metaspace add_prefix_space=true for transformers.js parity

Test: single-Metaspace pre_tokenizer for transformers.js parity

Add fp32 encoder for int8-vs-fp32 browser parity test

Re-export encoder at opset 14 (decomposed LayerNorm) for onnxruntime-web compatibility

int8 encoder (feature-extraction) for triple autofill

initial commit