Retrained adapter, 5000 iters, all 7 projections, ROUGE-L 0.41

Update adapter_config for 5000-iter retrain (LR 2e-4, all 7 projections)

Update model card with 2026-05-12 retrain metrics

Add adapter config

Update adapter: LoRA rank-16, 1500 iters, full Bitext dataset (27 intents)

Initial commit: LoRA adapter + model card