fix(frontend): only redirect to /login when the session check returns 401/403

src/context/UserContext.tsx

@@ -23,9 +23,20 @@ export const UserContext = ({ initialUser, children }: UserContextProps) => {
   }, [router.pathname, revalidate]);
 
   useEffect(() => {
+    // Only treat the session as invalid when the server actually rejected
+    // it. A check that never completed (e.g. the fetch was aborted because
+    // the user navigated away, or the server was briefly unreachable)
+    // rejects without a response; redirecting on those kicks logged-in
+    // users to /login and can even cancel an in-flight navigation to
+    // another site, dragging the browser back to the app. A transiently
+    // empty user (first fetch still in flight) must not navigate either —
+    // unauthenticated page loads are already redirected server-side.
+    const sessionInvalid =
+      error?.response?.status === 401 || error?.response?.status === 403;
+
     if (
       !router.pathname.match(/(setup|login|resetpassword)/) &&
-      (!user || error) &&
+      sessionInvalid &&
       !routing.current
     ) {
       routing.current = true;

src/hooks/useUser.ts

@@ -2,6 +2,7 @@ import { UserType } from '@server/constants/user';
 import type { PermissionCheckOptions } from '@server/lib/permissions';
 import { hasPermission, Permission } from '@server/lib/permissions';
 import type { NotificationAgentKey } from '@server/lib/settings';
+import type { AxiosError } from 'axios';
 import { useRouter } from 'next/router';
 import type { MutatorCallback } from 'swr';
 import useSWR from 'swr';
@@ -41,7 +42,7 @@ export interface UserSettings {
 interface UserHookResponse {
   user?: User;
   loading: boolean;
-  error: string;
+  error?: AxiosError;
   revalidate: (
     data?: User | Promise<User> | MutatorCallback<User> | undefined,
     shouldRevalidate?: boolean | undefined