Honor the client registration override only in setup and recovery

The recovery administrator signs in before any OAuth client is
registered, so it needs to skip the registration check. Outside
bootstrap and recovery mode, every account now signs in through a
registered client and one of its redirect URIs.

crates/http/src/auth/oauth/registration.rs

@@ -270,8 +270,12 @@ impl ClientRegistrationHandler for Server {
             false
         };
 
-        // Check if the account is allowed to override client registration
-        if self
+        // Check if the account is allowed to override client registration.
+        // inbuxa: only while setting up or recovering, when the recovery
+        // administrator signs in before any client is registered (contract C-5)
+        let registry = self.registry();
+        if (registry.is_bootstrap_mode() || registry.is_recovery_mode())
+            && self
                 .access_token(account_id)
                 .await
                 .caused_by(trc::location!())?