The slideover toggle button now uses a fixed light theme (white bg,
dark arrow) so it's always visible on the map regardless of OS dark
mode. Removed prefers-color-scheme overrides since the button overlays
the always-light map tiles.
Fixed map not resizing when closing the sidebar — the #aprs-map div
has phx-update="ignore" so server-rendered classes never updated.
Now uses LiveView JS commands (JS.toggle_class + JS.dispatch) to
toggle classes client-side and trigger map.invalidateSize(), replacing
the custom push_event/handleEvent JS handler.
Graham McIntire
976b6f153f