Route operatingBy.carrier lookups through operatingCarrier()

Several components still read `flight.operatingBy.carrier` directly.
The API actually returns `{scheduled, actual}` — I kept `.carrier` on
IOperatingBy as a deprecated alias during the refactor, so nothing
fails typechecking, but at runtime the lookup is always undefined,
which silently disabled the Registration, Flight-status and
Operated-by UIs (the Reg button did nothing on click, the status
visibility check always returned false).

Swap the affected sites — RegistrationButton, FlightStatusButton, the
canRegister / canViewFlightStatus visibility helpers, and the
'Operated by' block in OnlineBoardDetailsPage — to use the
operatingCarrier() helper that reads actual/scheduled/legacy in turn.

src/features/online-board/components/BoardDetailsHeader/FlightStatusButton.tsx

@@ -1,6 +1,6 @@
 import type { FC } from "react";
 import { useTranslation } from "@/i18n/provider.js";
-import type { ISimpleFlight } from "../../types.js";
+import { operatingCarrier, type ISimpleFlight } from "../../types.js";
 import { AIRLINES } from "./airlines.js";
 import { buildOnlineBoardUrl } from "../../url.js";
 import "./actions.scss";
@@ -15,7 +15,7 @@ export const FlightStatusButton: FC<FlightStatusButtonProps> = ({ flight, locale
   const { t } = useTranslation();
 
   const handleClick = () => {
-    const carrier = flight.operatingBy.carrier;
+    const carrier = operatingCarrier(flight.operatingBy);
     if (!carrier) return;
     const config = AIRLINES[carrier];
     if (!config) return;

src/features/online-board/components/BoardDetailsHeader/RegistrationButton.tsx

@@ -1,6 +1,6 @@
 import type { FC } from "react";
 import { useTranslation } from "@/i18n/provider.js";
-import type { ISimpleFlight } from "../../types.js";
+import { operatingCarrier, type ISimpleFlight } from "../../types.js";
 import { AIRLINES } from "./airlines.js";
 import "./actions.scss";
 
@@ -12,7 +12,10 @@ export const RegistrationButton: FC<RegistrationButtonProps> = ({ flight }) => {
   const { t } = useTranslation();
 
   const handleClick = () => {
-    const carrier = flight.operatingBy.carrier;
+    // IOperatingBy is `{scheduled, actual}` on real API payloads. The old
+    // `.carrier` shape survives as a deprecated alias; read through the
+    // helper so both work.
+    const carrier = operatingCarrier(flight.operatingBy);
     if (!carrier) return;
     const config = AIRLINES[carrier];
     if (!config?.registrationUrl) return;

src/features/online-board/components/BoardDetailsHeader/visibility/flightStatusVisibility.ts

@@ -1,5 +1,5 @@
 import { parseISO, subHours, isAfter, isSameDay } from "date-fns";
-import type { ISimpleFlight } from "../../../types.js";
+import { operatingCarrier, type ISimpleFlight } from "../../../types.js";
 
 /**
  * Flight Status button is visible when:
@@ -13,7 +13,7 @@ export function canViewFlightStatus(
   availableFromHours: number,
   airlinesWithStatus: Set<string>,
 ): boolean {
-  const carrier = flight.operatingBy.carrier;
+  const carrier = operatingCarrier(flight.operatingBy);
   if (!carrier || !airlinesWithStatus.has(carrier)) return false;
 
   const leg = flight.routeType === "Direct" ? flight.leg : flight.legs[0];

src/features/online-board/components/BoardDetailsHeader/visibility/registrationVisibility.ts

@@ -1,4 +1,4 @@
-import type { ISimpleFlight } from "../../../types.js";
+import { operatingCarrier, type ISimpleFlight } from "../../../types.js";
 import type { AirlineConfig } from "../airlines.js";
 
 /**
@@ -10,7 +10,7 @@ export function canRegister(
   flight: ISimpleFlight,
   airlineConfig: Record<string, AirlineConfig>,
 ): boolean {
-  const carrier = flight.operatingBy.carrier;
+  const carrier = operatingCarrier(flight.operatingBy);
   if (!carrier) return false;
   const config = airlineConfig[carrier];
   if (!config?.registrationUrl) return false;

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

@@ -31,6 +31,7 @@ import { FlightSchedule } from "./FlightSchedule/index.js";
 import { FullRouteTimeline } from "./FullRouteTimeline/index.js";
 import { TransferBar } from "./TransferBar/index.js";
 import type { IParsedFlightId, IFlightLeg } from "../types.js";
+import { operatingCarrier } from "../types.js";
 import {
   formatLocalTime,
   formatUtcOffset,
@@ -361,14 +362,17 @@ export const OnlineBoardDetailsPage: FC<OnlineBoardDetailsPageProps> = ({
             <FlightCard flight={displayFlight} />
 
             {/* Operating carrier */}
-            {displayFlight.operatingBy.carrier && (
-              <div className="flight-details__operating" data-testid="operating-carrier">
-                {t("BOARD.OPERATED-BY")}: {displayFlight.operatingBy.carrier}
-                {displayFlight.operatingBy.flightNumber
-                  ? ` ${displayFlight.operatingBy.flightNumber}`
-                  : ""}
-              </div>
-            )}
+            {(() => {
+              const opCarrier = operatingCarrier(displayFlight.operatingBy);
+              const opNumber = displayFlight.operatingBy.flightNumber;
+              if (!opCarrier) return null;
+              return (
+                <div className="flight-details__operating" data-testid="operating-carrier">
+                  {t("BOARD.OPERATED-BY")}: {opCarrier}
+                  {opNumber ? ` ${opNumber}` : ""}
+                </div>
+              );
+            })()}
 
             {/* Detailed leg information */}
             <FlightLegs legs={legs} viewType="Onlineboard" />