Pause on landing + auto-unpause on dispatch (ISS-041)

Replace the ISS-011 auto-slow with pause-on-landing: when the last plane
in flight lands, tickOnce sets sim_state.paused=true WITHOUT touching
timeScale (speed preserved). flyPlane() now clears paused before
persisting so starting a flight resumes a paused sim — inside runAction(),
tick + unpause + dispatch are atomic under the sim lock.

Tests: engine.test.ts auto-slow block rewritten for pause semantics; new
flyPlane test asserts dispatch clears paused with speed untouched. E2E:
auto-slow.spec.ts renamed to pause-on-landing.spec.ts asserting the new
behavior (paused=true AND timeScale still 1000 after landing; /fly clears
paused). Cross-cutting fix: every per-spec setScale helper now POSTs
{timeScale, paused:false} — a scale-only fast-forward after a landing would
otherwise leave the clock frozen. Deliberate mid-test pauses untouched.

lib/game/actions.ts

@@ -125,6 +125,9 @@ export async function flyPlane(inst: GameDb, planeId: string, destIcao: string):
       lon: origin.lon,
     })
     .where(eq(schema.planes.id, planeId));
+  // ISS-041: starting a flight resumes a paused sim (the last landing pauses it). Runs inside
+  // runAction(), so tick + unpause + dispatch are atomic under the sim lock.
+  await inst.db.update(schema.simState).set({ paused: false });
   await persist(inst);
 }