feat: amber indicator during post-close wind-down buffer

Parks in the 1-hour buffer after scheduled close now show amber instead
of green: the dot on the desktop calendar turns yellow, and the mobile
card badge changes from "Open today" (green) to "Closing" (amber).

- getOperatingStatus() replaces isWithinOperatingWindow's inline logic,
  returning "open" | "closing" | "closed"; isWithinOperatingWindow now
  delegates to it so all callers are unchanged
- closingParkIds[] is computed server-side and threaded through
  HomePageClient → WeekCalendar/MobileCardList → ParkRow/ParkCard
- New --color-closing-* CSS variables mirror the green palette in amber

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

components/WeekCalendar.tsx

@@ -12,6 +12,7 @@ interface WeekCalendarProps {
   grouped?: Map<Region, Park[]>; // pre-grouped parks (if provided, renders region headers)
   rideCounts?: Record<string, number>; // parkId → open ride/coaster count for today
   coastersOnly?: boolean;
+  closingParkIds?: string[]; // parks in the post-close wind-down buffer
 }
 
 const DOW = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
@@ -188,6 +189,7 @@ function ParkRow({
   parkData,
   rideCounts,
   coastersOnly,
+  closingParkIds,
 }: {
   park: Park;
   parkIdx: number;
@@ -196,9 +198,11 @@ function ParkRow({
   parkData: Record<string, DayData>;
   rideCounts?: Record<string, number>;
   coastersOnly?: boolean;
+  closingParkIds?: string[];
 }) {
   const rowBg = parkIdx % 2 === 0 ? "var(--color-bg)" : "var(--color-surface)";
   const tzAbbr = getTimezoneAbbr(park.timezone);
+  const isClosing = closingParkIds?.includes(park.id) ?? false;
   return (
     <tr
       className="park-row"
@@ -234,9 +238,11 @@ function ParkRow({
                   width: 7,
                   height: 7,
                   borderRadius: "50%",
-                  background: "var(--color-open-text)",
+                  background: isClosing ? "var(--color-closing-text)" : "var(--color-open-text)",
                   flexShrink: 0,
-                  boxShadow: "0 0 5px var(--color-open-text)",
+                  boxShadow: isClosing
+                    ? "0 0 5px var(--color-closing-text)"
+                    : "0 0 5px var(--color-open-text)",
                 }} />
               )}
             </div>
@@ -245,7 +251,7 @@ function ParkRow({
             </div>
           </div>
           {rideCounts?.[park.id] !== undefined && (
-            <div style={{ fontSize: "0.72rem", color: "var(--color-open-hours)", fontWeight: 600, whiteSpace: "nowrap", flexShrink: 0 }}>
+            <div style={{ fontSize: "0.72rem", color: isClosing ? "var(--color-closing-hours)" : "var(--color-open-hours)", fontWeight: 600, whiteSpace: "nowrap", flexShrink: 0 }}>
               {rideCounts[park.id]} {coastersOnly
                 ? (rideCounts[park.id] === 1 ? "coaster" : "coasters")
                 : (rideCounts[park.id] === 1 ? "ride" : "rides")} operating
@@ -266,7 +272,7 @@ function ParkRow({
   );
 }
 
-export function WeekCalendar({ parks, weekDates, data, grouped, rideCounts, coastersOnly }: WeekCalendarProps) {
+export function WeekCalendar({ parks, weekDates, data, grouped, rideCounts, coastersOnly, closingParkIds }: WeekCalendarProps) {
   const today = getTodayLocal();
   const parsedDates = weekDates.map(parseDate);
 
@@ -382,6 +388,7 @@ export function WeekCalendar({ parks, weekDates, data, grouped, rideCounts, coas
                   parkData={data[park.id] ?? {}}
                   rideCounts={rideCounts}
                   coastersOnly={coastersOnly}
+                  closingParkIds={closingParkIds}
                 />
               ))}
             </Fragment>