fix(map): draw the hotel-to-hotel leg on a transfer day with no activities (#1297)

On a day whose only content is checking out of one accommodation and into another, there are no waypoints for the hotel bookends to attach to, so no line was drawn. Add the A->B leg directly when both bookend hotels are real (excluding the day-1 arrival fallback per #1321) and distinct, so an ordinary same-hotel rest day still draws nothing.

client/tests/integration/hooks/useRouteCalculation.test.ts

@@ -322,6 +322,55 @@ describe('useRouteCalculation', () => {
     expect(legs).toContainEqual([`${actB.lat},${actB.lng}`, `${hotel.lat},${hotel.lng}`]);
   });
 
+  it('FE-HOOK-ROUTE-016: #1297 transfer day with no activities draws the hotel → hotel leg', async () => {
+    // Day 2 is a pure transfer: check out of hotel A (slept there last night) and into
+    // hotel B tonight, with no activities or transport. The map must still draw A → B.
+    const hotelA = { lat: 48.86, lng: 2.35 };
+    const hotelB = { lat: 45.76, lng: 4.84 };
+    const accommodations = [
+      { id: 1, start_day_id: 1, end_day_id: 2, place_lat: hotelA.lat, place_lng: hotelA.lng },
+      { id: 2, start_day_id: 2, end_day_id: 3, place_lat: hotelB.lat, place_lng: hotelB.lng },
+    ];
+    const store = { assignments: {} } as unknown as TripStoreState;
+    useTripStore.setState({
+      assignments: {},
+      reservations: [],
+      days: [{ id: 1, day_number: 1 }, { id: 2, day_number: 2 }, { id: 3, day_number: 3 }],
+    } as any);
+
+    const { result } = renderHook(() =>
+      useRouteCalculation(store, 2, true, 'driving', accommodations as any)
+    );
+
+    await act(async () => {});
+
+    const legs = (result.current.route ?? []).map(run => run.map(p => `${p[0]},${p[1]}`));
+    expect(legs).toContainEqual([`${hotelA.lat},${hotelA.lng}`, `${hotelB.lat},${hotelB.lng}`]);
+  });
+
+  it('FE-HOOK-ROUTE-017: #1297 rest day in one hotel with no activities draws nothing', async () => {
+    // Guard against a zero-length loop: morning and evening hotel are the same, no
+    // activities — no transfer leg should be drawn.
+    const hotel = { lat: 48.86, lng: 2.35 };
+    const accommodations = [
+      { id: 1, start_day_id: 1, end_day_id: 4, place_lat: hotel.lat, place_lng: hotel.lng },
+    ];
+    const store = { assignments: {} } as unknown as TripStoreState;
+    useTripStore.setState({
+      assignments: {},
+      reservations: [],
+      days: [{ id: 1, day_number: 1 }, { id: 2, day_number: 2 }, { id: 3, day_number: 3 }],
+    } as any);
+
+    const { result } = renderHook(() =>
+      useRouteCalculation(store, 2, true, 'driving', accommodations as any)
+    );
+
+    await act(async () => {});
+
+    expect(result.current.route).toBeNull();
+  });
+
   it('FE-HOOK-ROUTE-012: setRoute and setRouteInfo are exposed', () => {
     const store = buildMockStore({});
     const { result } = renderHook(() =>