Two bugs found on first hardware test:
1. page_home placed all widgets directly on the page with no sized
wrapper container, unlike every other page in this codebase (which
all wrap content in an explicit width/height obj before using
align:). The dial and its siblings rendered tiny and pinned to the
top-left instead of filling/centering on the real 1024x600 screen.
Wrapped all of page_home's content in a width:100%/height:100% obj,
matching the established pattern.
2. heat_arc and cool_arc were both adjustable:true at the identical
400x400 size, so their rings occupied the same physical pixels.
LVGL hit-tests arcs by distance from center, so a shared radius is
touch-ambiguous, and the topmost widget (cool_arc, declared last)
won every touch regardless of where on the ring you tapped. Shrunk
cool_arc to 360x360 so the two rings are physically distinguishable
by touch position.