feat: coaster filter toggle on homepage

- 🎢 Coasters button in nav bar (URL-driven: ?coasters=1)
- When active, swaps ride counts for coaster counts per park
- Label switches between "X rides operating" / "X coasters operating"
- Arrow key navigation preserves coaster filter state
- Only shown when coaster data exists in park-meta

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

app/page.tsx

@@ -8,9 +8,10 @@ import { openDb, getDateRange } from "@/lib/db";
 import { getTodayLocal, isWithinOperatingWindow } from "@/lib/env";
 import { fetchLiveRides } from "@/lib/scrapers/queuetimes";
 import { QUEUE_TIMES_IDS } from "@/lib/queue-times-map";
+import { readParkMeta, getCoasterSet } from "@/lib/park-meta";
 
 interface PageProps {
-  searchParams: Promise<{ week?: string }>;
+  searchParams: Promise<{ week?: string; coasters?: string }>;
 }
 
 function getWeekStart(param: string | undefined): string {
@@ -45,6 +46,7 @@ function getCurrentWeekStart(): string {
 export default async function HomePage({ searchParams }: PageProps) {
   const params = await searchParams;
   const weekStart = getWeekStart(params.week);
+  const coastersOnly = params.coasters === "1";
   const weekDates = getWeekDates(weekStart);
   const endDate = weekDates[6];
   const today = getTodayLocal();
@@ -61,7 +63,11 @@ export default async function HomePage({ searchParams }: PageProps) {
 
   // Fetch live ride counts for parks open today (cached 5 min via Queue-Times).
   // Only shown when the current time is within 1h before open to 1h after close.
+  const parkMeta = readParkMeta();
+  const hasCoasterData = PARKS.some((p) => (parkMeta[p.id]?.coasters.length ?? 0) > 0);
+
   let rideCounts: Record<string, number> = {};
+  let coasterCounts: Record<string, number> = {};
   if (weekDates.includes(today)) {
     const openTodayParks = PARKS.filter((p) => {
       const dayData = data[p.id]?.[today];
@@ -70,14 +76,23 @@ export default async function HomePage({ searchParams }: PageProps) {
     });
     const results = await Promise.all(
       openTodayParks.map(async (p) => {
-        const result = await fetchLiveRides(QUEUE_TIMES_IDS[p.id], null, 300);
-        const count = result ? result.rides.filter((r) => r.isOpen).length : 0;
-        return [p.id, count] as [string, number];
+        const coasterSet = getCoasterSet(p.id, parkMeta);
+        const result = await fetchLiveRides(QUEUE_TIMES_IDS[p.id], coasterSet, 300);
+        const rideCount = result ? result.rides.filter((r) => r.isOpen).length : 0;
+        const coasterCount = result ? result.rides.filter((r) => r.isOpen && r.isCoaster).length : 0;
+        return { id: p.id, rideCount, coasterCount };
       })
     );
-    rideCounts = Object.fromEntries(results.filter(([, count]) => count > 0));
+    rideCounts = Object.fromEntries(
+      results.filter(({ rideCount }) => rideCount > 0).map(({ id, rideCount }) => [id, rideCount])
+    );
+    coasterCounts = Object.fromEntries(
+      results.filter(({ coasterCount }) => coasterCount > 0).map(({ id, coasterCount }) => [id, coasterCount])
+    );
   }
 
+  const activeCounts = coastersOnly ? coasterCounts : rideCounts;
+
   const visibleParks = PARKS.filter((park) =>
     weekDates.some((date) => data[park.id]?.[date]?.isOpen)
   );
@@ -137,6 +152,8 @@ export default async function HomePage({ searchParams }: PageProps) {
             weekStart={weekStart}
             weekDates={weekDates}
             isCurrentWeek={isCurrentWeek}
+            coastersOnly={coastersOnly}
+            hasCoasterData={hasCoasterData}
           />
           <div className="hidden sm:flex">
             <Legend />
@@ -157,7 +174,8 @@ export default async function HomePage({ searchParams }: PageProps) {
                 weekDates={weekDates}
                 data={data}
                 today={today}
-                rideCounts={rideCounts}
+                rideCounts={activeCounts}
+                coastersOnly={coastersOnly}
               />
             </div>
 
@@ -168,7 +186,8 @@ export default async function HomePage({ searchParams }: PageProps) {
                 weekDates={weekDates}
                 data={data}
                 grouped={grouped}
-                rideCounts={rideCounts}
+                rideCounts={activeCounts}
+                coastersOnly={coastersOnly}
               />
             </div>
           </>