fix: read database URL from secrets.yaml as fallback

configData.database?.url was removed from the prod configmap (database
credentials belong in secrets), but the code only checked configData.
Add secretsData.database?.url as a fallback so prod can supply the URL
via the gateway-secrets Secret.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

gateway/src/main.ts

@@ -86,7 +86,7 @@ function loadConfig() {
       'http://localhost:5173',
       'http://localhost:8080',
     ],
-    databaseUrl: configData.database?.url || process.env.DATABASE_URL || 'postgresql://localhost/dexorder',
+    databaseUrl: configData.database?.url || secretsData.database?.url || process.env.DATABASE_URL || 'postgresql://localhost/dexorder',
 
     // Authentication configuration
     authSecret: secretsData.auth?.secret || process.env.AUTH_SECRET || 'change-me-in-production',