feat(ml): add GBDT and random forest implementations

feat: add hyperparameter grid search wrapper

feat: add CNN vs ViT benchmark script (untrained)

refactor: restructure into domain-grounded directories (ml/ cv/ gen/ graph/ rl/ nlp/)

move: lora/ → nlp/lora/

feat: add LoRA (parameter-efficient fine-tuning for GPT)

feat: add MobileNet (depthwise separable convolutions)

feat: add GCN, DQN, SimCLR, YOLO (4 new models + notebooks)

fix: regenerate notebooks with get_device() from utils.device

refactor: extract device detection to utils/device.py (CUDA→MPS→CPU)

feat: add P2+P3 notebooks (basics 9, Word2Vec, LSTM)

feat: add P1 notebooks for CNN, BERT, ResNet18, ResNet34

feat: add Jupyter notebooks for GPT, ViT, DCGAN, UNet