Update flights-map barrel and MF expose from stub to real

Populate the feature barrel with all 4A-4D exports. Replace the
FlightsMap MF expose stub with lazy-loaded FlightsMapStartPage,
gated by the flightsMap feature flag.

src/features/flights-map/index.ts

@@ -1,2 +1,40 @@
 // Public barrel for the flights-map feature. See frozen-barrels.md.
-export {};
+
+// 4A -- Types
+export type {
+  FlightsMapSearchParams,
+  FlightsMapCalendarParams,
+  IFlightRoute,
+  IDestinationsResponse,
+  IFlightsMapDaysResponse,
+  IMapMarker,
+  IMapPolyline,
+  IMapPopup,
+  MarkerStyle,
+  PolylineStyle,
+  IFlightsMapFilterState,
+} from "./types.js";
+
+// 4A -- API functions
+export { searchDestinations, getFlightsMapCalendar } from "./api.js";
+
+// 4A -- React hooks
+export { useFlightsMapSearch } from "./hooks/useFlightsMapSearch.js";
+export type { UseFlightsMapSearchResult } from "./hooks/useFlightsMapSearch.js";
+export { useFlightsMapCalendar } from "./hooks/useFlightsMapCalendar.js";
+export type { UseFlightsMapCalendarResult } from "./hooks/useFlightsMapCalendar.js";
+export { useFeatureFlag } from "./hooks/useFeatureFlag.js";
+
+// 4D -- SEO builder functions
+export { buildFlightsMapSeo } from "./seo.js";
+export type { TFunction } from "./seo.js";
+
+// 4D -- JSON-LD builder functions
+export { buildFlightsMapJsonLd } from "./json-ld.js";
+
+// 4C -- Feature-specific page components
+export { FlightsMapStartPage } from "./components/FlightsMapStartPage.js";
+export { FlightsMapFilter } from "./components/FlightsMapFilter.js";
+export type { FlightsMapFilterProps } from "./components/FlightsMapFilter.js";
+export { ClientOnly } from "./components/ClientOnly.js";
+export type { ClientOnlyProps } from "./components/ClientOnly.js";

src/mf/expose/FlightsMap.tsx

@@ -1,17 +1,40 @@
-import type { HostContract } from "@/host-contract";
-
 /**
  * MF expose wrapper for the Flights Map feature.
- * Phase 4 (flights-map port) replaces the body with the real root.
+ *
+ * Lazy-loads the FlightsMapStartPage via React.lazy + Suspense.
+ * Gated by the flightsMap feature flag.
  */
+
+import { lazy, Suspense } from "react";
+import type { HostContract } from "@/host-contract";
+import { useFeatureFlag } from "@/features/flights-map/hooks/useFeatureFlag.js";
+
+const FlightsMapStartPage = lazy(() =>
+  import("@/features/flights-map/components/FlightsMapStartPage.js").then(
+    (m) => ({ default: m.FlightsMapStartPage }),
+  ),
+);
+
 export interface FlightsMapRemoteProps {
   hostContract: HostContract;
 }
 
 export default function FlightsMapRemote(_props: FlightsMapRemoteProps): JSX.Element {
+  const isEnabled = useFeatureFlag("flightsMap");
+
+  if (!isEnabled) {
     return (
       <div data-mf-expose="FlightsMap">
-      <p>Flights Map remote — stub. Populated in Phase 4.</p>
+        <p>Flights Map is currently unavailable.</p>
+      </div>
+    );
+  }
+
+  return (
+    <div data-mf-expose="FlightsMap">
+      <Suspense fallback={<div aria-busy="true">Loading Flights Map...</div>}>
+        <FlightsMapStartPage />
+      </Suspense>
     </div>
   );
 }