Make layout full-width on mobile with docked top/bottom bars

Remove max-width constraint and horizontal padding on small screens
so content goes edge-to-edge. Turn navigation and action bar lose
rounded corners on mobile and dock flush to top/bottom edges.
Desktop layout (sm: and up) is unchanged.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/components/turn-navigation.tsx

@@ -12,7 +12,7 @@ export function TurnNavigation() {
 	const activeCombatant = encounter.combatants[encounter.activeIndex];
 
 	return (
-		<div className="card-glow flex items-center gap-3 rounded-lg border border-border bg-card px-4 py-3">
+		<div className="card-glow flex items-center gap-3 border-border border-b bg-card px-4 py-3 sm:rounded-lg sm:border">
 			<Button
 				variant="ghost"
 				size="icon"