การบำรุงรักษาสิ้นสุดลงแล้ว

Summary: Migrating database access from static passwords to zero-trust mTLS client certificate authentication (Vault PKI) and enforcing multi-tenant privilege boundaries.

Scope: MariaDB cluster, backend API services, and CI/CD migration runners.

Impact:
* Brief intermittent connection drops (~5–10 min) during rolling restarts.
* Permanent deprecation of static database passwords and remote TCP root access.
* DB engine will reject direct DELETE queries (soft-delete enforcement).

Action Required: None for end-users; internal services will automatically transition to ephemeral X.509 certificates.