feat(board): persist category collapse state in localStorage for guests (#5714)

* feat(board): persist category collapse state in localStorage for guests

Authenticated users already had their collapse state saved server-side.
This extends the same behaviour to unauthenticated (guest) users by
reading/writing localStorage keyed by section ID.

On mount, if the user is a guest, the stored value is applied to the
disclosure. On toggle, guests write to localStorage instead of calling
the protected API mutation.

Closes #3355

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* refactor: set localStorage value as useDisclosure default instead of useEffect

Replaces the useEffect that read localStorage after mount with a direct
initial value computation passed to useDisclosure. Removes the effect,
the open/close destructuring, and the useEffect import.

Note: initialCollapsed is computed during render rather than post-mount,
which may cause a hydration mismatch on SSR if localStorage differs from
the server-provided section.collapsed. The typeof window guard handles
the SSR case.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/nextjs/src/components/board/sections/category-section.tsx

@@ -3,6 +3,7 @@ import { useDisclosure } from "@mantine/hooks";
 import { IconChevronDown, IconChevronUp } from "@tabler/icons-react";
 
 import { clientApi } from "@homarr/api/client";
+import { useSession } from "@homarr/auth/client";
 import { useRequiredBoard } from "@homarr/boards/context";
 
 import type { CategorySection } from "~/app/[locale]/boards/_types";
@@ -10,19 +11,36 @@ import { CategoryMenu } from "./category/category-menu";
 import { GridStack } from "./gridstack/gridstack";
 import classes from "./item.module.css";
 
+const localStorageKey = (sectionId: string) => `homarr-section-collapsed-${sectionId}`;
+
 interface Props {
   section: CategorySection;
 }
 
 export const BoardCategorySection = ({ section }: Props) => {
+  const { status } = useSession();
   const { mutate } = clientApi.section.changeCollapsed.useMutation();
   const board = useRequiredBoard();
-  const [opened, { toggle }] = useDisclosure(section.collapsed, {
+
+  const initialCollapsed =
+    typeof window !== "undefined"
+      ? (localStorage.getItem(localStorageKey(section.id)) ?? String(section.collapsed)) === "true"
+      : section.collapsed;
+
+  const [opened, { toggle }] = useDisclosure(initialCollapsed, {
     onOpen() {
-      mutate({ sectionId: section.id, collapsed: true });
+      if (status === "authenticated") {
+        mutate({ sectionId: section.id, collapsed: true });
+      } else if (status === "unauthenticated") {
+        localStorage.setItem(localStorageKey(section.id), "true");
+      }
     },
     onClose() {
-      mutate({ sectionId: section.id, collapsed: false });
+      if (status === "authenticated") {
+        mutate({ sectionId: section.id, collapsed: false });
+      } else if (status === "unauthenticated") {
+        localStorage.setItem(localStorageKey(section.id), "false");
+      }
     },
   });