The Spotify Canvas fallback layout previously centered the panel+artwork
group on screenFrame.midY, so the enlarged artwork tile could push up
into the row of circular widgets (battery, audio, AQI, weather).
Clamp maxCenterY against the bottom edge of both
LockScreenWeatherPanelManager.latestFrame and
LockScreenTimerWidgetPanelManager.latestFrame, with a 20pt clearance,
and guard against the clamp inverting via max(maxCenterY, minCenterY).
The panel reflows through the existing
.atollLockScreenPanelFrameDidChange notification, so the artwork
overlay window follows the new panel position automatically.
Signed-off-by: Jis G Jacob <studiokeys@blissroms.org>