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/db/client.ts

@@ -30,7 +30,8 @@ CREATE TABLE IF NOT EXISTS planes (
   dest_icao TEXT,
   lat REAL NOT NULL,
   lon REAL NOT NULL,
-  departure_sim_time INTEGER
+  departure_sim_time INTEGER,
+  queue TEXT NOT NULL DEFAULT '[]'
 );
 CREATE TABLE IF NOT EXISTS packages (
   id TEXT PRIMARY KEY NOT NULL,
@@ -72,6 +73,10 @@ function migrateColumns(raw: RawSqlJsDatabase): void {
   if (!cols('planes').has('dest_icao')) {
     raw.exec('ALTER TABLE planes ADD COLUMN dest_icao TEXT');
   }
+  // v0.25.0 (ISS-043): the flight queue — ordered JSON array of not-yet-started leg ICACs.
+  if (!cols('planes').has('queue')) {
+    raw.exec(`ALTER TABLE planes ADD COLUMN queue TEXT NOT NULL DEFAULT '[]'`);
+  }
 }
 
 // v0.12.0 one-time migration: contracts world → packages world. Detected by the
@@ -159,7 +164,9 @@ async function seedEmpty(instance: GameDb): Promise<void> {
   const rng = mulberry32(randomInt(0, 2 ** 31));
   const data = buildSeed({ airports, rng, nowMs: Date.now() });
 
-  await instance.db.insert(schema.planes).values(data.plane);
+  // SeedPlane.queue is a string[]; the column stores it as JSON text.
+  const { queue, ...planeCols } = data.plane;
+  await instance.db.insert(schema.planes).values({ ...planeCols, queue: JSON.stringify(queue ?? []) });
   await instance.db.insert(schema.packages).values(data.packages);
   await instance.db.insert(schema.account).values(data.account);
   await instance.db.insert(schema.simState).values(data.simState);