Flight queue backend: planes hold a queue of upcoming legs, auto-chain on landing (ISS-043 part 1)

- planes.queue TEXT NOT NULL DEFAULT '[]' — ordered JSON array of not-yet-started
  leg ICACs; active leg stays destIcao + departureSimTime. DDL + guarded ALTER
  migration for existing DBs; seed sets queue: [] explicitly.
- deliverPackages() auto-chains on arrival: with a non-empty queue and fuel
  covering the first queued leg (same requiredFuelFor rule as /fly), the plane
  immediately starts that leg from the arrival airport (stays 'flying',
  departureSimTime = arrival instant, queue shortened). Short tank → grounds
  safely with the queue kept intact; empty queue → unchanged grounding. Cargo
  delivery for the reached airport runs first and is unaffected. Ordering kept:
  delivery still runs before tickOnce's pause check, so a chained plane counts
  as still flying — no premature last-plane pause (ISS-041 preserved).
- New endpoints via performAction(): POST /api/planes/{planeId}/queue {destIcao}
  (append; works grounded or flying; 400 bad body/unknown ICAO, 404 unknown
  plane) and POST /api/planes/{planeId}/queue/cancel {index} (remove queued leg
  by index; active in-flight leg never affected; 400 non-integer/out-of-range,
  404 unknown plane). Both return the full state snapshot.
- PlaneState.queue: string[] in /api/state (null/malformed-safe parse helper
  shared with the engine); OpenAPI updated (PlaneState.queue, QueueLegRequest,
  CancelQueuedLegRequest, both paths) and openapi.test.ts expectations extended.
- Tests: auto-chain block in engine.test.ts (chain / short-fuel ground / empty
  queue) + chained-plane-no-pause regression guard; queueLeg/cancelQueuedLeg
  blocks in actions.test.ts; type-compat queue: [] fixtures in deriveEvents,
  right-pane, mapData and seed tests.

v0.25.0 — part 1 (backend) of ISS-043; UI/map rendering lands in a follow-up.

lib/game/actions.test.ts

@@ -13,9 +13,11 @@ import { HUB_ICAO } from './seed';
 import {
   abandonPackage,
   buyPlane,
+  cancelQueuedLeg,
   flyPlane,
   GameActionError,
   loadPackage,
+  queueLeg,
   refuelPlane,
   sellPlane,
 } from './actions';
@@ -206,6 +208,75 @@ describe('flyPlane', () => {
   });
 });
 
+describe('queueLeg (v0.25.0, ISS-043)', () => {
+  it('appends legs to the queue in order and persists them as JSON', async () => {
+    const inst = await freshDb('qleg-ok.db');
+
+    await queueLeg(inst, 'plane-starter', 'LEMD');
+    let plane = (await inst.db.select().from(schema.planes))[0];
+    expect(JSON.parse(plane.queue)).toEqual(['LEMD']);
+
+    await queueLeg(inst, 'plane-starter', 'EHAM'); // pre-building a route
+    plane = (await inst.db.select().from(schema.planes))[0];
+    expect(JSON.parse(plane.queue)).toEqual(['LEMD', 'EHAM']); // order preserved
+  });
+
+  it('works on a flying plane too — the active leg is untouched, nothing auto-starts', async () => {
+    const inst = await freshDb('qleg-flying.db');
+    await inst.db.update(schema.planes)
+      .set({ status: 'flying', departureSimTime: T0, destIcao: 'LEMD' })
+      .where(eq(schema.planes.id, 'plane-starter'));
+
+    await queueLeg(inst, 'plane-starter', 'EHAM');
+
+    const plane = (await inst.db.select().from(schema.planes))[0];
+    expect(plane.status).toBe('flying'); // still on its active leg…
+    expect(plane.destIcao).toBe('LEMD'); // …unchanged — queueing never starts a flight
+    expect(JSON.parse(plane.queue)).toEqual(['EHAM']);
+  });
+
+  it('rejects an unknown plane id with 404', async () => {
+    const inst = await freshDb('qleg-ghost.db');
+    await expectActionError(queueLeg(inst, 'ghost', 'LEMD'), 404);
+  });
+
+  it('rejects an ICAO not in the airport dataset with 400', async () => {
+    const inst = await freshDb('qleg-unknownicao.db');
+    await expectActionError(queueLeg(inst, 'plane-starter', 'ZZZZ'), 400, /unknown airport/);
+  });
+});
+
+describe('cancelQueuedLeg (v0.25.0, ISS-043)', () => {
+  it('removes the leg at the given index and keeps the rest in order', async () => {
+    const inst = await freshDb('qcancel-ok.db');
+    await queueLeg(inst, 'plane-starter', 'LEMD');
+    await queueLeg(inst, 'plane-starter', 'EHAM');
+    await queueLeg(inst, 'plane-starter', 'EDDV');
+
+    await cancelQueuedLeg(inst, 'plane-starter', 1); // drop EHAM (the middle leg)
+
+    const plane = (await inst.db.select().from(schema.planes))[0];
+    expect(JSON.parse(plane.queue)).toEqual(['LEMD', 'EDDV']);
+  });
+
+  it('rejects an out-of-range index with 400', async () => {
+    const inst = await freshDb('qcancel-oob.db');
+    await queueLeg(inst, 'plane-starter', 'LEMD'); // one leg → only index 0 is valid
+    await expectActionError(cancelQueuedLeg(inst, 'plane-starter', 1), 400);
+    await expectActionError(cancelQueuedLeg(inst, 'plane-starter', -1), 400);
+  });
+
+  it('rejects cancelling from an empty queue with 400', async () => {
+    const inst = await freshDb('qcancel-empty.db'); // seeded starter has no queued legs
+    await expectActionError(cancelQueuedLeg(inst, 'plane-starter', 0), 400);
+  });
+
+  it('rejects an unknown plane id with 404', async () => {
+    const inst = await freshDb('qcancel-ghost.db');
+    await expectActionError(cancelQueuedLeg(inst, 'ghost', 0), 404);
+  });
+});
+
 describe('abandonPackage', () => {
   // A loaded package created at T0 with a 10h window; the seeded sim clock is T0.
   const REWARD = 1_000;