Single sign-on servers need no setup step

With single sign-on there is no first-start code and no /setup form: the
identity provider says who may sign in and who is admin, and the first
allowed sign-in makes the organisation, named after ARCHIFY_SYNC_NAME.
Server 0.1.1, chart 0.1.2.

crates/server/src/pages.rs

@@ -531,9 +531,12 @@ async fn sso_account(
             .invite_organisation(&auth::sha256(invite))
             .await?
             .map(|(org, _)| org),
-        None if !config.allowed_groups.is_empty() || admin => {
-            state.store.first_organisation().await?
-        }
+        None if !config.allowed_groups.is_empty() || admin => Some(
+            state
+                .store
+                .organisation_or_create(&state.config.server_name)
+                .await?,
+        ),
         None => None,
     };
     let Some(organisation) = organisation else {