improve: redesign mobile card layout for usability

Replace the cramped 7-column day grid with a clean open-days list.
Each card now shows:
- Park name + "Open today" / "Closed today" badge in the header
- One row per open day (Today, Monday, Friday...) with full hours
- Today row highlighted in amber; passholder days labeled inline
- Whole card is a tap target linking to the park detail page

Also:
- Hide the legend below sm breakpoint (not needed on phones)
- Reduce horizontal padding to 16px on mobile (was 24px)
- Tighten MobileCardList vertical spacing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

components/MobileCardList.tsx

@@ -12,7 +12,7 @@ interface MobileCardListProps {
 
 export function MobileCardList({ grouped, weekDates, data, today }: MobileCardListProps) {
   return (
-    <div style={{ display: "flex", flexDirection: "column", gap: 24, paddingTop: 16 }}>
+    <div style={{ display: "flex", flexDirection: "column", gap: 20, paddingTop: 14 }}>
       {Array.from(grouped.entries()).map(([region, parks]) => (
         <div key={region} data-region={region}>
           {/* Region heading */}