Laya r4 (local model)

Laya language detection model, round 4: laya-r3 fully fine-tuned on 199,600 new wrong-layout examples (Tatoeba, gen_data.py).

Word accuracy on 1,000 held-out-sentence examples (identical readings count as one choice): 99.9% (r3: 97.8%) - Ukrainian 99.8%, Russian 100%, English 100%.

laya-r3 is unchanged. Requirements for local inference: laya-requirements.txt.