add correct RPE1 block backbone (SO4^32 theta=192). backbones/rpe1/epoch350 is NON-BLOCK (theta=4096) — do not use with block flow.

add RPE1 block flow checkpoint (trained on block backbone)

fix: add correct RPE1 block checkpoint (SO4^32, theta=192). epoch350_periodic was non-block.

Initial NeurIPS 2026 release: backbones, flow heads, SciPlex3 Path-B teachers/students, paper-table result JSONs

initial commit