Wire QR overview create-code links into the two-step add-funds modal

The dashboard 'Create code' / 'Create your first code' links were plain hrefs
to the create page, so a user with insufficient balance only met the top-up
modal after filling the form. Gate them with balanceGate + mount the modal so
they open Add funds directly when the wallet can't cover a QR code.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/Http/Controllers/Qr/OverviewController.php

@@ -4,6 +4,7 @@ namespace App\Http\Controllers\Qr;
 
 use App\Http\Controllers\Controller;
 use App\Models\QrCode;
+use App\Models\QrWallet;
 use App\Services\Billing\BillingClient;
 use App\Services\Qr\QrCodeManagerService;
 use App\Support\Qr\QrTypeCatalog;
@@ -56,6 +57,7 @@ class OverviewController extends Controller
             'activeCount' => $activeCount,
             'scans30d' => (int) $scans30d,
             'balanceMinor' => $balanceMinor,
+            'pricePerQr' => QrWallet::pricePerQr(),
         ]);
     }
 }