feat(items): re-enable lazy loading with cursor

example: if a folder has many resource, client will use lazy loading
    and load next cursor if scroll reached the bottom of the page
    purpose: reduce the amount of call to server

frontend/src/routes/files/page.test.ts

@@ -46,12 +46,10 @@ vi.mock('$lib/api/endpoints/files', () => ({
 	uploadFileWithProgress: vi.fn()
 }));
 vi.mock('$lib/api/endpoints/folders', () => ({
-	cacheFolder: vi.fn(),
 	createFolder: vi.fn(),
 	deleteFolder: vi.fn(),
-	fetchFolderListing: vi.fn(),
+	fetchFolderPage: vi.fn(),
 	folderZipUrl: () => '/zip',
-	getCachedFolder: () => undefined,
 	getFolder: vi.fn(async (id: string) => ({ id, name: id })),
 	getFolderName: () => undefined,
 	invalidateFolderCache: vi.fn(),
@@ -60,7 +58,7 @@ vi.mock('$lib/api/endpoints/folders', () => ({
 	renameFolder: vi.fn()
 }));
 
-import { fetchFolderListing, createFolder, deleteFolder } from '$lib/api/endpoints/folders';
+import { fetchFolderPage, createFolder, deleteFolder } from '$lib/api/endpoints/folders';
 import { deleteFile } from '$lib/api/endpoints/files';
 import { apiFetch } from '$lib/api/client';
 import { files as filesStore } from '$lib/stores/files.svelte';
@@ -69,15 +67,17 @@ import FilesPage from './[...path]/+page.svelte';
 const m = (fn: unknown) => fn as ReturnType<typeof vi.fn>;
 
 function withListing() {
-	m(fetchFolderListing).mockResolvedValue({
-		status: 200,
-		etag: 'v1',
-		listing: {
-			folders: [folderItem('sub1', 'Sub')],
-			files: [fileItem('f1', 'hello.txt')],
-			favoriteIds: [],
-			sharedIds: []
-		}
+	// `fetchFolderPage` returns ONE page with the accumulator shape (items in
+	// server order + folders/files splits). With `nextCursor` omitted the
+	// caller treats it as the last page — the page's items become the whole
+	// on-screen listing without triggering `loadMore`.
+	const folder = folderItem('sub1', 'Sub');
+	const file = fileItem('f1', 'hello.txt');
+	m(fetchFolderPage).mockResolvedValue({
+		items: [folder, file],
+		folders: [folder],
+		files: [file],
+		nextCursor: undefined
 	});
 }
 
@@ -131,27 +131,18 @@ beforeEach(() => {
 });
 
 it('loads the home folder listing on mount and renders its contents', async () => {
-	m(fetchFolderListing).mockResolvedValue({
-		status: 200,
-		etag: 'v1',
-		listing: {
-			folders: [folderItem('sub1', 'Sub')],
-			files: [fileItem('f1', 'hello.txt')],
-			favoriteIds: [],
-			sharedIds: []
-		}
-	});
+	withListing();
 	render(FilesPage);
-	await waitFor(() => expect(fetchFolderListing).toHaveBeenCalledWith('home', expect.anything()));
+	await waitFor(() => expect(fetchFolderPage).toHaveBeenCalledWith('home', expect.anything()));
 	// VirtualList windows rows by viewport height (0 in jsdom), so assert the
 	// surrounding chrome rendered rather than the windowed rows themselves.
 	await screen.findByTestId('files-new-folder-btn');
 });
 
 it('shows an error when the listing fails with no cache', async () => {
-	m(fetchFolderListing).mockRejectedValue(Object.assign(new Error('nope'), { status: 500 }));
+	m(fetchFolderPage).mockRejectedValue(Object.assign(new Error('nope'), { status: 500 }));
 	render(FilesPage);
-	await waitFor(() => expect(fetchFolderListing).toHaveBeenCalled());
+	await waitFor(() => expect(fetchFolderPage).toHaveBeenCalled());
 });
 
 it('redirects external users away from the home folder', async () => {