fix(frontend): use proper env variable for image

frontend/src/app/layout.tsx

@@ -14,7 +14,7 @@
 }) {
   const API_ENDPOINT = process.env.RODOLF_API_URL;
   const APP_TITLE = process.env.RODOLF_APP_TITLE;
-  const APP_LOGO = process.env.RODOLF_APP_LOGO;
+  const APP_LOGO = process.env.RODOLF_APP_LOGO_B64;
 
   if (!API_ENDPOINT) {
     console.error("No api endpoint configured");