v1.0: lab07: fine-tuning QLoRA/LoRA para assistente de barbearia

Dataset sintético gerado via OpenAI, pipeline de treinamento com
BitsAndBytes 4-bit NF4, LoRA (r=64, alpha=16, dropout=0.1) e
SFTTrainer com paged_adamw_32bit + cosine scheduler.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>