ui: reflect readonly mode by hiding controls + various small styling fixes

app/src/ui/routes/data/data.$entity.index.tsx

@@ -169,6 +169,8 @@ function EntityCreateButton({ entity }: { entity: Entity }) {
          media: b.app.config.media.entity_name,
       };
       if (system.users === entity.name) {
+         if (b.readonly) return null;
+
          return (
             <Button onClick={createUserModal.open} variant="primary">
                New User