v1.48.1

Persistent event history for the monitor (#2 follow-up). v1.48.0's alerts had no memory — an OOM kill at 3 a.m. lived in Telegram scrollback, or on headless installs only in the container log. Monitor events are now persisted (atomic, latest 200) and shown in a Container Events section on the Web UI's History page, rendered through the same i18n keys as the live notifications. "What happened last night?" now has an answer in the browser.