Fixed world clock: no player time controls (ISS-117)

The world always runs at WORLD_TIME_SCALE = 24 (lib/worldClock.ts). A server
background tick (instrumentation.ts -> startBackgroundTick, 1 s interval)
advances the sim with no open browser; idle-pause freezes the clock exactly
while no plane is flying or in repair. Fresh worlds start year 2000
(STARTING_CLOCK_MS in seed.ts).

- Removed: POST /api/sim + OpenAPI entry, applyTimeControls/clampTimeScale,
  lib/timeScale.ts, LeftPane pause button + scale slider machinery,
  ISS-057 slow-on-landing/resume in flyPlane.
- Snapshot simState is now { clockMs } only; client extrapolates at the fixed
  rate between polls and freezes while idle (useSimClock).
- New test-only hook POST /api/test/set-timescale behind FLIGHT_TEST_HOOKS=1
  (sibling of set-health); all e2e setScale helpers call it, afterEach restores
  the world rate. E2E pause tests replaced by idle-pause assertions; sim.spec.ts
  activates the world via set-health + /repair for advance/expiry tests.

lib/game/actions.ts

@@ -173,14 +173,6 @@ export async function flyPlane(inst: GameDb, planeId: string, destIcao: string):
   if (cost > 0) {
     await inst.db.update(schema.account).set({ cash: Math.round((account.cash - cost) * 100) / 100 });
   }
-  // ISS-057: dispatch still resumes a MANUALLY paused sim (pause is manual-only now — landings
-  // slow to 1× instead of pausing), and restores the last manually selected speed when this
-  // dispatch took the LAST grounded plane airborne. Runs inside runAction(), so tick + controls
-  // + dispatch are atomic under the sim lock.
-  const sets: Partial<Pick<schema.SimStateRow, 'paused' | 'timeScale'>> = { paused: false };
-  const remaining = await inst.db.select().from(schema.planes).where(eq(schema.planes.status, 'available'));
-  if (remaining.length === 0) sets.timeScale = sim.lastSelectedTimeScale;
-  await inst.db.update(schema.simState).set(sets);
   await persist(inst);
 }