demo app layout issues on mobile

[sargunv]

since the latest redesign of the demo app, I've mostly been testing on desktop viewports and the mobile layout has rotten a bit:

• the menu feels like a side nav bar that should be draggable but it's not draggable
• consider bringing back a bottom sheet or other overlay control only when a demo is active, only on narrow viewports, since the menu nav must collapse to view the map

Resolved:

• theme toggle button (below zoom) doesn't have fixed size like the other buttons (demo: stack overlay controls under the compass #1310)
• insets are applied twice, not properly consumed, causing a weird "forehead" on the menu (fix: stop double-applying safe insets in the demo panel #1308)
• the maplibre logo jumps down for a moment when the style switches (fix: decouple MapLibre logo layout from attribution button #1309)
• consider moving zoom, theme toggle buttons just below compass instead of middle (demo: stack overlay controls under the compass #1310)
• consider replacing location demo with a location / follow mode button next to those, and location provider setting in settings (demo: move location follow onto the overlay stack #1311)