Restore date defaults to today so search forms submit correctly

Null dates broke form submission — the handlers bail early when date
is null. Restore initialization to today/+7 days as before. The
Calendar placeholder prop still provides the format hint when cleared.

src/features/online-board/components/OnlineBoardFilter.tsx

@@ -55,13 +55,13 @@ export const OnlineBoardFilter: FC = () => {
 
   // Flight number fields
   const [flightNumber, setFlightNumber] = useState("");
-  const [flightDate, setFlightDate] = useState<Date | null>(null);
+  const [flightDate, setFlightDate] = useState<Date | null>(new Date());
   const [flightNumberError, setFlightNumberError] = useState<string | null>(null);
 
   // Route fields
   const [routeDeparture, setRouteDeparture] = useState<CitySuggestion | string>("");
   const [routeArrival, setRouteArrival] = useState<CitySuggestion | string>("");
-  const [routeDate, setRouteDate] = useState<Date | null>(null);
+  const [routeDate, setRouteDate] = useState<Date | null>(new Date());
   const [timeRange, setTimeRange] = useState<[number, number]>([0, 1440]);
 
   // City autocomplete search

src/features/schedule/components/ScheduleStartPage.tsx

@@ -51,13 +51,13 @@ export const ScheduleStartPage: FC = () => {
 
   const [departureAirport, setDepartureAirport] = useState<CitySuggestion | string>("");
   const [arrivalAirport, setArrivalAirport] = useState<CitySuggestion | string>("");
-  const [dateFrom, setDateFrom] = useState<Date | null>(null);
-  const [dateTo, setDateTo] = useState<Date | null>(null);
+  const [dateFrom, setDateFrom] = useState<Date | null>(today);
+  const [dateTo, setDateTo] = useState<Date | null>(addDays(today, 7));
   const [timeRange, setTimeRange] = useState<[number, number]>([0, 1440]);
   const [directOnly, setDirectOnly] = useState(false);
   const [isRoundTrip, setIsRoundTrip] = useState(false);
-  const [returnDateFrom, setReturnDateFrom] = useState<Date | null>(null);
-  const [returnDateTo, setReturnDateTo] = useState<Date | null>(null);
+  const [returnDateFrom, setReturnDateFrom] = useState<Date | null>(addDays(today, 7));
+  const [returnDateTo, setReturnDateTo] = useState<Date | null>(addDays(today, 14));
   const [returnTimeRange, setReturnTimeRange] = useState<[number, number]>([0, 1440]);
 
   // City autocomplete search