Two-plane load fix + e2e coverage (ISS-055, v0.31.0)

- LoadControls preselects the first eligible plane so Load is one-click with N planes
- LeftPane queue testids scoped by plane id (queue-leg/cancel/add[-dest]-{plane.id})
  — unscoped ids duplicated in the DOM with two on-board blocks
- new POST /api/test/add-cash hook (FLIGHT_TEST_HOOKS=1, default €1M) so e2e can
  afford a second plane; returns the full state snapshot
- new serial spec e2e/two-planes.spec.ts: load, parallel fly + ISS-057 slow/resume,
  refuel, relocate, per-plane queues with auto-chain, sell (6 tests)
- e2e/queue.spec.ts locators updated to the scoped testids

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## v0.31.0 — 2026-09-20 21:23
+- **Two-plane Load is one-click again (ISS-055).** The reported "can't load cargo with two planes at the same airport" was UX, not a server bug: `LoadControls` (`components/RightPane.tsx`) rendered a plane picker for ≥2 eligible planes whose Load button stayed DISABLED until a pick existed, while the single-plane path is one-click. The multi-plane path now PRESELECTS the first eligible plane (`effective = … ?? eligible[0] ?? null`; the select already bound to `effective?.id`), so Load is enabled and one-click whenever ≥1 plane qualifies — the dropdown still allows picking a different plane
+- **LeftPane queue testids scoped by plane id (ISS-055).** With two on-board blocks in the DOM the unscoped ids duplicated: `queue-leg-{i}` → `queue-leg-{plane.id}-{i}`, `queue-cancel-{i}` → `queue-cancel-{plane.id}-{i}`, plus the add control `queue-add-dest`/`queue-add` → `queue-add-dest-{plane.id}`/`queue-add-{plane.id}` (`components/LeftPane.tsx`). The shared pane-level destination pick is unchanged. `e2e/queue.spec.ts` locators updated to the scoped form (single-plane fleet, id `plane-starter`)
+- **New test hook: POST /api/test/add-cash (ISS-055).** Grants cash so e2e can afford a second plane (ATR €200k vs the €20k starting balance) — body `{ amount?: number }` (positive finite, default €1M), gated on `FLIGHT_TEST_HOOKS=1` exactly like its siblings (`app/api/test/create-package`, `/expire-package`; same 404/400 error shape), returns the full state snapshot. Test-only: outside the OpenAPI spec, so the documented path list stays at thirteen
+- **New serial e2e spec `e2e/two-planes.spec.ts` (ISS-055).** Six tests covering every two-plane gameplay flow — each buys its own second ATR via the UI (after an add-cash grant) and discovers it in /api/state as the plane that isn't `plane-starter`: **load** (picker lists both planes, preselect makes Load one-click without touching the select, explicit pick routes to the other plane, both on-board blocks render with cargo simultaneously), **fly** (parallel dispatch to different destinations; ISS-057 semantics — last landing leaves `paused === false && timeScale === 1`, dispatching a plane while another is grounded stays at 1×, dispatching the LAST grounded plane resumes `lastSelectedTimeScale` = 1000 in the /fly response), **refuel** (left-pane section lists both planes; refueling one deducts exactly its fill-up cost and tops only that tank), **relocate** (moves one plane, starter untouched), **queue** (per-plane scoped controls add/cancel independently; landing auto-chains the next queued leg at 1000×), **sell** (payout = round(price × SELL_FRACTION) added to cash, fleet back to 1, selling the last remaining plane 409s via API). Robust reset: beforeEach heals + sells every non-starter plane (queue cleared first so landings can't auto-chain mid-heal, leftover cargo abandoned so the sell guard never 409s) and repositions the starter home — every test starts AND ends at fleet = 1
+- Verified: `tsc --noEmit` clean; unit suite green locally (327 passed in 32 files — unchanged, no new unit tests: the sibling test hooks have none, so add-cash follows suit); `npx playwright test --list` = 52 tests in 14 files (was 46/13 — six new two-plane tests); e2e not run locally by design — CI verifies against an isolated stack
+
 ## v0.30.0 — 2026-09-20 19:47
 - **Landing slows the sim to 1× instead of pausing; dispatch restores the last selected speed (ISS-057).** Replaces the v0.24.0 pause-on-landing behavior with a slow-down: in `tickOnce` (`lib/sim/engine.ts`), when ≥1 plane landed this tick and ANY plane is grounded ('available') afterwards, the sim drops to `MIN_TIME_SCALE` (1×) — a just-landed plane counts, so any real landing slows; a chained plane stays 'flying' via deliverPackages' auto-chain branch, so a pure-chain tick with nothing grounded does NOT slow. Pause becomes manual-only: ticks never set it anymore
 - **Resume on dispatch.** `flyPlane` (`lib/game/actions.ts`) still clears a manually-paused sim on dispatch (kept), and now ALSO restores the last manually selected speed when this dispatch took the LAST grounded plane airborne — fresh-select 'available' planes after the update, and if zero remain set `timeScale = lastSelectedTimeScale`. With another plane still grounded the sim stays at 1×