feat: UI redesign with park detail pages and ride status

Visual overhaul:
- Warmer color system with amber accent for Today, better text hierarchy
- Row hover highlighting, sticky column shadow on horizontal scroll
- Closed cells replaced with dot (·) instead of "Closed" text
- Regional grouping (Northeast/Southeast/Midwest/Texas & South/West)
- Two-row header with park count badge and WeekNav on separate lines
- Amber "Today" button in WeekNav when off current week
- Mobile card layout (< 1024px) with 7-day grid per park; table on desktop
- Skeleton loading state via app/loading.tsx

Park detail pages (/park/[id]):
- Month calendar view with ← → navigation via ?month= param
- Live ride status fetched from Six Flags API (cached 1h)
- Ride hours only shown when they differ from park operating hours
- Fallback to nearest upcoming open day when today is dropped by API,
  including cross-month fallback for end-of-month edge case

Data layer:
- Park type gains region field; parks.ts exports groupByRegion()
- db.ts gains getParkMonthData() for single-park month queries
- sixflags.ts gains scrapeRidesForDay() returning RidesFetchResult
  with rides, dataDate, isExact, and parkHoursLabel

Removed: CalendarGrid.tsx, MonthNav.tsx (dead code)

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

components/MobileCardList.tsx

@@ -0,0 +1,60 @@
+import type { Park } from "@/lib/scrapers/types";
+import type { DayData } from "@/lib/db";
+import type { Region } from "@/lib/parks";
+import { ParkCard } from "./ParkCard";
+
+interface MobileCardListProps {
+  grouped: Map<Region, Park[]>;
+  weekDates: string[];
+  data: Record<string, Record<string, DayData>>;
+  today: string;
+}
+
+export function MobileCardList({ grouped, weekDates, data, today }: MobileCardListProps) {
+  return (
+    <div style={{ display: "flex", flexDirection: "column", gap: 24, paddingTop: 16 }}>
+      {Array.from(grouped.entries()).map(([region, parks]) => (
+        <div key={region} data-region={region}>
+          {/* Region heading */}
+          <div style={{
+            display: "flex",
+            alignItems: "center",
+            gap: 10,
+            marginBottom: 10,
+            paddingLeft: 2,
+          }}>
+            <div style={{
+              width: 3,
+              height: 14,
+              borderRadius: 2,
+              background: "var(--color-region-accent)",
+              flexShrink: 0,
+            }} />
+            <span style={{
+              fontSize: "0.65rem",
+              fontWeight: 700,
+              letterSpacing: "0.1em",
+              textTransform: "uppercase",
+              color: "var(--color-text-muted)",
+            }}>
+              {region}
+            </span>
+          </div>
+
+          {/* Park cards */}
+          <div style={{ display: "flex", flexDirection: "column", gap: 8 }}>
+            {parks.map((park) => (
+              <ParkCard
+                key={park.id}
+                park={park}
+                weekDates={weekDates}
+                parkData={data[park.id] ?? {}}
+                today={today}
+              />
+            ))}
+          </div>
+        </div>
+      ))}
+    </div>
+  );
+}