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/openapi.ts

@@ -204,6 +204,74 @@ export const openApiSpec = {
         },
       },
     },
+    '/api/planes/{planeId}/queue': {
+      post: {
+        summary: 'Queue a flight leg for a plane',
+        description:
+          'Append a NOT-yet-started leg to the plane\'s flight queue (v0.25.0, ISS-043). Works whether the plane is grounded or flying — you can pre-build a route; the active leg still starts via /fly and nothing auto-starts here. On landing, the engine auto-chains the first queued leg when fuel covers it (otherwise the plane grounds with the queue kept intact for refuel + re-dispatch).',
+        operationId: 'queueLeg',
+        parameters: [
+          { name: 'planeId', in: 'path', required: true, schema: { type: 'string' } },
+        ],
+        requestBody: {
+          required: true,
+          content: {
+            'application/json': {
+              schema: { $ref: '#/components/schemas/QueueLegRequest' },
+            },
+          },
+        },
+        responses: {
+          200: {
+            description: 'Queued — full state snapshot (plane.queue now includes the new leg)',
+            content: { 'application/json': { schema: { $ref: '#/components/schemas/StateSnapshot' } } },
+          },
+          400: {
+            description:
+              'Invalid body (not an object, unknown field, or missing/non-string destIcao) or the ICAO is not in the airport dataset',
+            content: { 'application/json': { schema: { $ref: '#/components/schemas/Error' } } },
+          },
+          404: {
+            description: 'Unknown plane id',
+            content: { 'application/json': { schema: { $ref: '#/components/schemas/Error' } } },
+          },
+        },
+      },
+    },
+    '/api/planes/{planeId}/queue/cancel': {
+      post: {
+        summary: 'Cancel a queued flight leg',
+        description:
+          'Remove a NOT-yet-started leg from the plane\'s queue by index (v0.25.0, ISS-043). Only queued legs are cancellable — the active in-flight leg (destIcao) is never affected.',
+        operationId: 'cancelQueuedLeg',
+        parameters: [
+          { name: 'planeId', in: 'path', required: true, schema: { type: 'string' } },
+        ],
+        requestBody: {
+          required: true,
+          content: {
+            'application/json': {
+              schema: { $ref: '#/components/schemas/CancelQueuedLegRequest' },
+            },
+          },
+        },
+        responses: {
+          200: {
+            description: 'Cancelled — full state snapshot (plane.queue without the removed leg)',
+            content: { 'application/json': { schema: { $ref: '#/components/schemas/StateSnapshot' } } },
+          },
+          400: {
+            description:
+              'Invalid body (not an object, unknown field, or non-integer index) or the index is outside [0, queue.length)',
+            content: { 'application/json': { schema: { $ref: '#/components/schemas/Error' } } },
+          },
+          404: {
+            description: 'Unknown plane id',
+            content: { 'application/json': { schema: { $ref: '#/components/schemas/Error' } } },
+          },
+        },
+      },
+    },
     '/api/market/buy-plane': {
       post: {
         summary: 'Buy a plane from the market',
@@ -441,6 +509,20 @@ export const openApiSpec = {
         },
         required: ['destIcao'],
       },
+      QueueLegRequest: {
+        type: 'object',
+        properties: {
+          destIcao: { type: 'string', description: 'Any airport ICAO from the dataset — appended to the queue as a not-yet-started leg (v0.25.0).' },
+        },
+        required: ['destIcao'],
+      },
+      CancelQueuedLegRequest: {
+        type: 'object',
+        properties: {
+          index: { type: 'integer', description: 'Zero-based position of the queued (not-yet-started) leg to remove; must be within [0, queue.length) (v0.25.0).' },
+        },
+        required: ['index'],
+      },
       BuyPlaneRequest: {
         type: 'object',
         properties: {
@@ -502,6 +584,12 @@ export const openApiSpec = {
           },
           lat: { type: 'number' },
           lon: { type: 'number' },
+          queue: {
+            type: 'array',
+            items: { type: 'string' },
+            description:
+              'Upcoming flight legs NOT yet started (v0.25.0) — ordered ICAOs; the active leg is destIcao. The engine auto-chains queue[0] on landing when fuel covers it.',
+          },
         },
         required: [
           'id',
@@ -516,6 +604,7 @@ export const openApiSpec = {
           'departureSimTime',
           'lat',
           'lon',
+          'queue',
         ],
       },
       PackageState: {