polish: mobile view layout and usability improvements

Header:
- Hide "X of Y parks open this week" badge on mobile (hidden sm:inline-flex)
  — title + Coaster Mode button fit cleanly on a 390px screen

WeekNav:
- Arrow button padding 6px 14px → 10px 16px, minWidth: 44px for proper
  touch targets (Apple HIG recommends 44px minimum)
- Date label minWidth 200px → 140px, prevents crowding on small screens

ParkCard:
- Name container: flex: 1, minWidth: 0 so long park names don't push
  the status badge off-screen; name wraps naturally instead of overflowing
- Timezone abbreviation: opacity: 0.6 → color: var(--color-text-dim),
  semantic dimming instead of opacity for better accessibility
- Passholder label: 0.58rem → 0.65rem (was below WCAG minimum)

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

components/HomePageClient.tsx

@@ -118,7 +118,7 @@ export function HomePageClient({
               </button>
             )}
 
-            <span style={{
+            <span className="hidden sm:inline-flex" style={{
               background: visibleParks.length > 0 ? "var(--color-open-bg)" : "var(--color-surface)",
               border: `1px solid ${visibleParks.length > 0 ? "var(--color-open-border)" : "var(--color-border)"}`,
               borderRadius: 20,
@@ -126,6 +126,8 @@ export function HomePageClient({
               fontSize: "0.78rem",
               color: visibleParks.length > 0 ? "var(--color-open-hours)" : "var(--color-text-muted)",
               fontWeight: 600,
+              alignItems: "center",
+              whiteSpace: "nowrap",
             }}>
               {visibleParks.length} of {PARKS.length} parks open this week
             </span>