Remove production test scaffolding from useMapData and update MapPage tests

frontend/src/hooks/useMapData.ts

@@ -100,20 +100,3 @@ export function useMapData(
   };
 }
 
-/**
- * Test helper: returns arguments most recently used to call `useMapData`.
- *
- * This helper is only intended for test use with a mock implementation.
- */
-export function getLastArgs(): { range: string; origin: string } {
-  throw new Error("getLastArgs is only available in tests with a mocked useMapData");
-}
-
-/**
- * Test helper: mutates mocked map data state.
- *
- * This helper is only intended for test use with a mock implementation.
- */
-export function setMapData(_: Partial<UseMapDataResult>): void {
-  throw new Error("setMapData is only available in tests with a mocked useMapData");
-}