- updateEmailByCustomer: DB fallback when stripe_customer_id not in cache
- updateKeyEmail: DB fallback when key not in cache
- POST /v1/recover: DB fallback when email not in cache (was only on verify)
- 6 TDD tests added (keys-email-update.test.ts, recover-initial-db-fallback.test.ts)
- 547 tests total, all passing