Don't force a username — let Cloudron let the user choose it during setup

app/main.py

@@ -171,12 +171,12 @@ async def cloudron_create_user(email: str, name: str) -> str:
             if u.get("email") == email:
                 return u["id"]
 
-        # Create user (role "user" = regular member)
+        # Create user (role "user" = regular member). Only email is required;
+        # Cloudron lets the user choose their own username during account setup.
         r = await client.post(
             f"{CLOUDRON_API}/api/v1/users",
             headers=cloudron_headers(),
             json={
-                "username": email.split("@")[0],
                 "email": email,
                 "displayName": name,
                 "role": "user",