Reject duplicate queue legs — same route can no longer be queued twice (ISS-065, v0.34.0)

e2e/queue.spec.ts

@@ -233,6 +233,10 @@ test('queue display + cancel via UI (ISS-043 part 2)', async ({ page }) => {
   }, { timeout: 15_000, message: 'waiting for the fly click to take effect (status "flying" + dest set)' }).toBe(true);
   await postSim(page, { paused: true }); // pause-sim pattern: deterministic window for UI clicks
 
+  // ISS-065: re-queuing the CURRENT leg's destination while flying must be rejected with 409.
+  const dupQueue = await page.request.post('/api/planes/plane-starter/queue', { data: { destIcao: DEST } });
+  expect(dupQueue.status()).toBe(409);
+
   // ADD a leg to the queue via the Relocate section (ISS-053): the starter is flying, so relocate-go
   // posts to /queue and the leg starts when it lands.
   await page.getByTestId('relocate-plane').selectOption('plane-starter');