fix: gate direct (entry-fee) payouts behind DIRECT_PAYOUTS_ENABLED

completeGame only gated PAID_CREDITS payouts (on creditsPayoutEnabled); a
PAID_SINGLE win paid out unconditionally, so DIRECT_PAYOUTS_ENABLED=false did
NOT actually stop direct payouts — a no-payout instance (mainnet legitimacy)
would still send crypto on an entry-fee win. Caught during deploy verification.

- Add this.directPayoutEnabled (from DIRECT_PAYOUTS_ENABLED env / direct rule
  enabled in the config snapshot), mirroring creditsPayoutEnabled.
- completeGame now gates the PAID_SINGLE payout on directPayoutEnabled.
- The derived directPayoutsEnabled flags (getGameModeInfo / effective mode)
  and /api/game-modes PAID_SINGLE.payoutMultiplier now respect it (show 0 when
  off) instead of inferring from multipliers > 0.

Adds a regression test: a PAID_SINGLE win with directPayoutEnabled=false
queues no payout. Full suite: 22 suites / 159 tests.

test/payoutSnapshot.test.js

@@ -89,4 +89,21 @@ describe('Payout uses the snapshot recorded at game start', () => {
 
     expect(result.payout.amount).toBe(200000000000); // live 2x
   });
+
+  test('no payout for a PAID_SINGLE win when direct payouts are disabled (no-payout instance)', async () => {
+    const { gmm, db } = buildGmm();
+    gmm.directPayoutEnabled = false; // e.g. mainnet legitimacy: sell entry, never pay out
+
+    db.query
+      .mockResolvedValueOnce({ rows: [{ id: 1, game_mode: 'PAID_SINGLE', payout_address: 'wow1addr' }] }) // game record
+      .mockResolvedValue({ rows: [] }); // completion UPDATE + anything else
+
+    const result = await gmm.completeGame('socket1', 'game123', true, true, { moves: 10 });
+
+    expect(result.success).toBe(true);
+    expect(result.payout == null || result.payout === undefined).toBe(true); // no payout queued
+    // No payout INSERT happened.
+    const insertedPayout = db.query.mock.calls.find(c => /INSERT INTO payouts/i.test(c[0]));
+    expect(insertedPayout).toBeUndefined();
+  });
 });