reworked admin auth to use form and cookie + adjusted oauth to support API and cookie-based auth

app/src/ui/client/schema/auth/use-bknd-auth.ts

@@ -19,6 +19,7 @@ export function useBkndAuth() {
             if (window.confirm(`Are you sure you want to delete the role "${name}"?`)) {
                return await bkndActions.remove("auth", `roles.${name}`);
             }
+            return false;
          }
       }
    };