Add supported versions for 2.4.8-p4, 2.4.7-p9, 2.4.6-p14, Mage-OS 2.2.0 (#315)

Prepare for the Magento security patch release on 2026-03-10.
Updates EOL dates for predecessor versions and adds test cases.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: rhoerr