ensured footer was pinned to bottom of page for new-ish billboard.html & room_scroll.html pages; introduced mobile landscape layout, incl. leftward 'navbar', rightward 'footer'; ensured z-index primacy of #id_kit_btn, which would here appear behind the kit bar when open; other fixes introduced by problems stemming largely from new landscape styling

src/static_src/scss/core.scss

@@ -6,6 +6,7 @@
 @import 'gameboard';
 @import 'palette-picker';
 @import 'room';
+@import 'billboard';
 @import 'game-kit';
 @import 'wallet-tokens';