Self-serve OAuth application creation fails with 503

[Zmstar83]

Trying to create an OAuth application via Settings -> Developer (the flow described in #687) fails at submission -- the request never completes and no application is created.

Steps to reproduce

1. Log in, go to sorare.com/settings/developer
2. Click Request an application
3. Fill in:
   • Application name: any name
   • Callback URLs: one https:// production URL and one http://localhost:3000/... dev URL
   • Logo: a PNG uploaded via Upload a logo
4. Click Create application

Expected

Per the modal's own text ("credentials are issued immediately"), the application should be created and a client_id/client_secret shown.

Actual

POST https://api.sorare.com/graphql returns 503 Service Unavailable. No application is created -- the "OAuth applications" section still shows "You haven't requested any OAuth application yet." No user-facing error message is displayed; the form just doesn't proceed.

Other issues noticed along the way (ruled out as the cause of the 503, but worth flagging)

• Logo silently required. Submitting without a logo throws an unhandled client-side JS exception instead of a validation message -- the field isn't marked with * like Application name is, so nothing indicates it's required.
• Confirmed this isn't an ad-blocker/client-network issue: reproduced with ad blockers fully disabled, in two separate browser sessions. The 503 is server-side.

Environment

• Reproduced consistently across multiple attempts, different browser sessions, ad blockers on and off