Group status now treats maintenance'd children like paused ones —
they're excluded from the UP/DOWN calculation. Prevents group from
showing DOWN when its only failing child is under maintenance.
Forms overflowed past terminal because huh didn't know about the
surrounding chrome (header, footer, padding). Now sets WithHeight()
on every render and forwards WindowSizeMsg during form state.
Maintenance windows suppress alerts during planned downtime while checks
continue running. Incidents provide informational tracking. Supports
targeting all monitors, single monitor, or group (applies to children).
New Maint tab in TUI with create/end/delete. Status page, JSON API, and
Prometheus metrics all reflect maintenance state.