Records the 12-month cadence and the trigger rules agreed in co-op/support#35,
a last-rotated table (first entry: the Open Collective token, rotated
2026-10-27; other rows blank because nothing is recorded), and the account map
behind the credentials. Adds scripts/rotation_due.py, which reads the table and
prints only when a credential is within 30 days of its due date.
