fix: dropdown and frontend

fix: made download background and ui sub menu for model select

fix: memory overload by adding top models and options to load singular models

refactor: fix the docs and dynamic model load

feat: v3 models - XGBoost R2=0.9866, GradientBoosting R2=0.9860 as default

feat: HF model repo at v1/v2 root; version selector UI with download submenu; artifacts/ out of git

feat: full project — ML simulation, dashboard UI, models on HF Hub