[FOLD] Logic to activate rotate/deletion.
Correct how we decide to rotate.
[FOLD]
[FOLD] clear prior ledgers
[FOLD] remove from SQLite
[FOLD] update and persist lastRotated
[FOLD] copy ledger [TODO] need to stop from visitNodes()
[FOLD] freshen caches
[FOLD] new backend, and function to persist backend names
[FOLD] clear ledger cache prior
[FOLD] clear full below, set generations
[FOLD] rotate and associated
[FOLD] delete old backend directory