feat: add nfcorpus quality eval for fp32 vs INT8

feat: land nfcorpus benches, encode batch_size, and INT8-negative docs

feat: add INT8 ONNX quantization with configurable backend file

test: add benchmarking suite and publish results

feat: add ONNX backend support

cleanup: renamed api endpoint /predict to /embed

feat: add dynamic batching and benchmark script