fix(promo-codes): register discover endpoint in ApiEndpointsSeeder

The GET /api/v1/summits/{id}/promo-codes/all/discover route was added in
Task 12 but never seeded into the api_endpoints table. The OAuth2 bearer
token validator middleware rejects any unregistered route with a 400
"API endpoint does not exits" error, causing 5 discover-endpoint integration
tests in OAuth2SummitPromoCodesApiTest to fail.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: caseylocker

database/seeders/ApiEndpointsSeeder.php

@@ -7591,6 +7591,15 @@ private function seedSummitEndpoints()
                     SummitScopes::ReadAllSummitData
                 ]
             ],
+            [
+                'name' => 'discover-promo-codes',
+                'route' => '/api/v1/summits/{id}/promo-codes/all/discover',
+                'http_method' => 'GET',
+                'scopes' => [
+                    SummitScopes::ReadSummitData,
+                    SummitScopes::ReadAllSummitData
+                ]
+            ],
             // speakers promo codes
             [
                 'name' => 'get-promo-code-speakers',