verify_rewards, verify_vhack_heldout, build_substrate, probe_distill, probe_plot_stack
are run via 'python -m' / justfile and imported by no core module -> moved to scripts/,
relative imports rewritten to 'from projected_grpo.X'. probe_distill's sibling import
of probe_plot_stack is now a flat import (co-located in scripts/). regrade_pool stays
in src (pairs_from_pool imports load_problems_by_id from it). justfile recipes updated.
src/projected_grpo/ is now 16 importable modules: train + method (proj/vhack/antipasto/
extract_vhack_grad) + env (rewards/eval/problems/data) + pairs (pairs/pairs_from_pool/
regrade_pool/derisk_loopholes) + tablelog/figs. ~1480 lines moved out of the package.
Smoke green (verify_rewards 52/52 from scripts/, train pipeline cout->0).
Co-Authored-By: Claudypoo <288921227+claudypoo@users.noreply.github.com>