Split pay into ladder/lib_pay.sh; force-select extract in
ladder/extract_rpubs.py. check_goa_ladder.sh is only a compat shim.
max-ladder now hunts highest withdrawable and highest payable
(never above wallet available), using public free-amount template
goa-free on hacktivism. Classic remains default 23-rung wd+pay.
Pay phase always runs when LADDER_PAY=1 (visible SKIP_BALANCE when
no spendable coins). Report includes best_pay / alt names.
