Owner pricing decision 2026-09-01: gold and standard now default to
rate_minor 500 ($5.00) per delivered issue; free stays 0. Defaults
only — SAAS_TIERS_JSON overrides still win, auto_merge untouched.
Also align the SAAS_RATE_MINOR fallback (DEFAULT_RATE_MINOR) to 500 so
the per-delivery default matches the new rate everywhere.
Tests updated to the literal 500/500/0 values and the $5.00 debits;
idempotent single-debit + replay-no-double-charge coverage already
existed (deliver:<repo>:<pr>:<head_sha> key) and now asserts 500.