v8: composite 0.5203 | GLEU 0.0000 | BERTScore 0.9349 | 1-WER 0.3191 | HumanScore 0.8272 | AIScore 0.1728 | coedit-large r=16 fixed-loss v8-stable-CE

Auto-upgrade v4: composite 0.8757 | GLEU 0.7792 | BERTScore 0.9793 | 1-WER 0.8687 | base=coedit-large, r=32, 256-token ctx, coedit+GEC data, faithfulness gate

Auto-upgrade v3: composite 0.8634 | GLEU 0.7593 | BERTScore 0.9758 | 1-WER 0.8552 | r=16, 256-token ctx, C4-GEC data, faithfulness gate

Auto-upgrade: composite 0.8576 | GLEU 0.7506 | BERTScore 0.9733 | 1-WER 0.8488 | r=16, 10 epochs, combined loss