IMU-only models: v2 (video-distilled, indoor specialist) + lam01 (outdoor)

IMU-only models: v2 (video-distilled, indoor specialist) + lam01 (outdoor)

document v3b

v3b: context branch on 7-domain corpus — best-in-class all domains

Update README.md

document v2b

add v2b: expanded-corpus model (L2D+comma2k19)

document context-branch experiments (v3/v4): negative result, data-diversity bottleneck

SpeedNet v2 + baseline: flow->CNN->GRU ego-speed, lap-time supervised

initial commit