Compute — thin cyclic sum covers

Replay the published Bevan–Erskine–Lewis infinite family and the Haanpää small-order table. Independent check:

python3 compute/make_bel_certs.py
python3 compute/haanpaa_replay.py
python3 compute/verify.py

verify.py does not import the construction code. It only recomputes A+A from the listed set.

Search residue (not a bound): search_linear_family.py, search_three_ap_wide.py, complete_sidon.py, greedy_complete.py, eval_algebraic.py, prune_two_ap.py.