Add integration coverage for multi-leg timeline and transfer-bar

Verifies FullRouteTimeline + TransferBar render for MultiLeg fixtures
and stay absent for Direct flights, locking in the B.5 page wiring.

tests/integration/online-board/flight-details.test.tsx

@@ -162,6 +162,40 @@ describe("Flight details page integration", () => {
     expect(screen.getByTestId("flight-leg-1")).toBeTruthy();
   });
 
+  it("renders FullRouteTimeline and a TransferBar between legs for multi-leg", () => {
+    setupWithFlight(MULTI_LEG_FLIGHT);
+    render(
+      <OnlineBoardDetailsPage
+        flightId={{
+          carrier: "SU",
+          flightNumber: "0300",
+          date: "20250115",
+        }}
+        locale="ru"
+        canonicalOrigin="https://www.aeroflot.ru"
+      />,
+    );
+    expect(screen.getByTestId("full-route-timeline")).toBeTruthy();
+    expect(screen.getAllByTestId("transfer-bar")).toHaveLength(1);
+    // transfer-bar should include the intermediate-landing label and a computed transfer-time
+    const bar = screen.getByTestId("transfer-bar");
+    expect(bar.textContent).toContain("SHARED.INTERMEDIATE-LANDING");
+    expect(bar.querySelector('[data-testid="transfer-time"]')).toBeTruthy();
+  });
+
+  it("does not render FullRouteTimeline or TransferBar for direct flight", () => {
+    setupWithFlight(DIRECT_FLIGHT);
+    render(
+      <OnlineBoardDetailsPage
+        flightId={FLIGHT_ID}
+        locale="ru"
+        canonicalOrigin="https://www.aeroflot.ru"
+      />,
+    );
+    expect(screen.queryByTestId("full-route-timeline")).toBeNull();
+    expect(screen.queryByTestId("transfer-bar")).toBeNull();
+  });
+
   it("renders operating carrier info", () => {
     setupWithFlight();
     render(