Fix: Filesystem Platform-based Folder Buttons

src/lib/components/library/LibraryToolbar.svelte

@@ -3,6 +3,7 @@
     MagnifyingGlass, Books, DownloadSimple, Folder, FolderSimple,
     SortAscending, CaretUp, CaretDown, ArrowsClockwise, Star, X, CheckSquare,
   } from "phosphor-svelte";
+  import { canOpenFolder }  from "$lib/core/filesystem";
   import LibraryFilters from "./LibraryFilters.svelte";
   import type { Category } from "$lib/types";
   import type { LibrarySortOption, LibrarySortDir, LibraryStatusFilter, LibraryContentFilter } from "$lib/state/library.svelte";
@@ -165,9 +166,11 @@
       </button>
     {/if}
 
+    {#if canOpenFolder()}
       <button class="icon-btn" title="Open downloads folder" onclick={onOpenDownloadsFolder}>
         <FolderSimple size={15} weight="bold" />
       </button>
+    {/if}
 
     <div class="sort-panel-wrap">
       <button

src/lib/components/series/SeriesActions.svelte

@@ -4,6 +4,7 @@
     CaretDown, ArrowsClockwise, List, SquaresFour, FolderSimplePlus,
     Trash, DownloadSimple, X, MagnifyingGlass, Funnel, Check, FolderOpen,
   } from 'phosphor-svelte'
+  import { canOpenFolder }  from '$lib/core/filesystem'
   import type { Chapter, Category } from '$lib/types'
   import type { ChapterSortMode, ChapterSortDir } from './lib/chapterList'
 
@@ -275,7 +276,7 @@
       <ArrowsClockwise size={14} weight="light" class={refreshing ? 'anim-spin' : ''} />
     </button>
 
-    {#if downloadedCount > 0}
+    {#if downloadedCount > 0 && canOpenFolder()}
       <button class="icon-btn" onclick={onOpenFolder} title="Open manga folder">
         <FolderOpen size={14} weight="light" />
       </button>

src/lib/core/filesystem.ts

@@ -16,11 +16,28 @@ function join(root: string, ...parts: string[]): string {
   return [root.replace(/[/\\]$/, ''), ...parts].join(sep)
 }
 
-function checkSupported(): boolean {
+function isLocalServer(): boolean {
+  try {
+    const host = new URL(settingsState.settings.serverUrl).hostname
+    return host === 'localhost' || host === '127.0.0.1' || host === '::1'
+  } catch {
+    return false
+  }
+}
+
+export function canOpenFolder(): boolean {
+  return platformService.isSupported('filesystem') && isLocalServer()
+}
+
+function checkCanOpenFolder(): boolean {
   if (!platformService.isSupported('filesystem')) {
     addToast({ kind: 'info', title: 'Desktop only', body: 'Opening folders requires the desktop app.' })
     return false
   }
+  if (!isLocalServer()) {
+    addToast({ kind: 'info', title: 'Remote server', body: 'Folder access is unavailable when connected to a remote server.' })
+    return false
+  }
   return true
 }
 
@@ -33,7 +50,7 @@ function checkRoot(root: string): boolean {
 }
 
 export async function openMangaFolder(manga: Manga): Promise<void> {
-  if (!checkSupported()) return
+  if (!checkCanOpenFolder()) return
   const root   = getDownloadsRoot()
   if (!checkRoot(root)) return
   const source = (manga as any).source?.displayName ?? (manga as any).source?.name ?? ''
@@ -44,14 +61,14 @@ export async function openMangaFolder(manga: Manga): Promise<void> {
 }
 
 export async function openDownloadsFolder(): Promise<void> {
-  if (!checkSupported()) return
+  if (!checkCanOpenFolder()) return
   const root = getDownloadsRoot()
   if (!checkRoot(root)) return
   await platformService.openPath(root).catch(console.error)
 }
 
 export async function openCustomFolder(path: string): Promise<void> {
-  if (!checkSupported()) return
+  if (!checkCanOpenFolder()) return
   if (!path?.trim()) return
   await platformService.openPath(path).catch(console.error)
 }