model card: standard structure, measured facts, verified license declarations

docs: refresh measured performance (local retest 2026-08-18)

docs: descriptive model card

rebuild-verification 2026-08-17: Linux rebuild reproduces weight.bin BIT-EXACT (sha256 f81f60eb…, 0/308,616,576 bytes differ) and model_config.json + tokenizer identical; encoder.mlmodelc container not reproducible off macOS (coremlcompiler)

embeddinggemma-300m Core ML bundle (ANE encoder) — production embedding model

initial commit