Fix schedule details date format

Upstream /schedule/details returns 400 when dates are sent as
yyyy-MM-dd; it wants the full ISO datetime (yyyy-MM-ddT00:00:00), same
as Angular's ApiFormatterService.formatDate output. Update the date
helper in ScheduleDetailsPage to append T00:00:00.

Verified with curl: request now returns 200 with the full flight
payload for SU1942 on 2026-04-18.

src/features/schedule/components/ScheduleDetailsPage.tsx

@@ -31,11 +31,12 @@ export interface ScheduleDetailsPageProps {
 }
 
 /**
- * Convert yyyyMMdd to yyyy-MM-dd for the API.
+ * Convert yyyyMMdd to yyyy-MM-ddT00:00:00 for the API (matches Angular's
+ * ApiFormatterService.formatDate).
  */
 function formatApiDate(yyyymmdd: string): string {
   if (yyyymmdd.length !== 8) return yyyymmdd;
-  return `${yyyymmdd.slice(0, 4)}-${yyyymmdd.slice(4, 6)}-${yyyymmdd.slice(6, 8)}`;
+  return `${yyyymmdd.slice(0, 4)}-${yyyymmdd.slice(4, 6)}-${yyyymmdd.slice(6, 8)}T00:00:00`;
 }
 
 /**