fix(desktop): show the file browser default in Appearance settings

Settings > Appearance > Window & layout gets a File Browser toggle bound to the same persisted state as the titlebar toggle and Cmd+J, so the open/closed default is a visible, searchable preference.

apps/desktop/src/app/settings/appearance-settings.tsx

@@ -26,6 +26,7 @@ import {
   setInterfaceMode
 } from '@/store/interface-mode'
 import { $introSplash, setIntroSplash } from '@/store/intro-splash'
+import { $fileBrowserOpen, setFileBrowserOpen } from '@/store/layout'
 import { notifyError } from '@/store/notifications'
 import { $activeGatewayProfile, $profiles, normalizeProfileKey } from '@/store/profile'
 import { $reactionsEnabled, setReactionsEnabled } from '@/store/reactions-enabled'
@@ -430,6 +431,7 @@ export function AppearanceSettings({ subpage }: AppearanceSettingsProps = {}) {
   const embedMode = useStore($embedMode)
   const embedAllowed = useStore($embedAllowed)
   const composerPopoutGesturesEnabled = useStore($composerPopoutGesturesEnabled)
+  const fileBrowserOpen = useStore($fileBrowserOpen)
   const translucency = useStore($translucency)
   const glassMode = translucency.mode === 'glass' && GLASS_SUPPORTED
   const userBubbleTransparency = useStore($userBubbleTransparency)
@@ -924,6 +926,18 @@ export function AppearanceSettings({ subpage }: AppearanceSettingsProps = {}) {
             />
           )}
 
+          {/* The same state as the titlebar toggle / ⌘J, which persists across
+              launches — so this is the file browser's standing default. */}
+          {show('window-layout') && (
+            <ToggleRow
+              checked={fileBrowserOpen}
+              description={a.fileBrowserDesc}
+              id={settingElementId(ids.fileBrowser)}
+              label={a.fileBrowserTitle}
+              onChange={setFileBrowserOpen}
+            />
+          )}
+
           {show('window-layout') && (
             <ToggleRow
               checked={composerPopoutGesturesEnabled}

apps/desktop/src/app/settings/file-browser-setting.test.tsx

@@ -0,0 +1,54 @@
+// @vitest-environment jsdom
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { act, cleanup, fireEvent, render, screen } from '@testing-library/react'
+import { afterEach, describe, expect, it } from 'vitest'
+
+import { $fileBrowserOpen, FILE_BROWSER_PANE_ID, setFileBrowserOpen, toggleFileBrowserOpen } from '@/store/layout'
+import { $paneStates } from '@/store/panes'
+
+import { AppearanceSettings } from './appearance-settings'
+
+// #65173: the file browser's open/closed default was only reachable through
+// ⌘J and a persistence chain nobody could see. Settings now states it, and it
+// is the same state the titlebar toggle writes — two views, one answer.
+
+afterEach(() => {
+  cleanup()
+  act(() => setFileBrowserOpen(false))
+})
+
+function fileBrowserSwitch() {
+  render(
+    <QueryClientProvider client={new QueryClient()}>
+      <AppearanceSettings subpage="window-layout" />
+    </QueryClientProvider>
+  )
+
+  return screen.getByRole('switch', { name: 'File Browser' })
+}
+
+describe('File Browser setting', () => {
+  it('turns the file browser on and off, and persists the choice', () => {
+    const toggle = fileBrowserSwitch()
+
+    expect(toggle.getAttribute('aria-checked')).toBe('false')
+
+    fireEvent.click(toggle)
+
+    expect($fileBrowserOpen.get()).toBe(true)
+    expect($paneStates.get()[FILE_BROWSER_PANE_ID]?.open).toBe(true)
+
+    fireEvent.click(toggle)
+
+    expect($fileBrowserOpen.get()).toBe(false)
+    expect($paneStates.get()[FILE_BROWSER_PANE_ID]?.open).toBe(false)
+  })
+
+  it('follows the titlebar toggle', () => {
+    const toggle = fileBrowserSwitch()
+
+    act(() => toggleFileBrowserOpen())
+
+    expect(toggle.getAttribute('aria-checked')).toBe('true')
+  })
+})

apps/desktop/src/app/settings/settings-manifest.ts

@@ -101,6 +101,11 @@ export const SETTINGS_MANIFEST = {
       available: () => TRANSLUCENCY_SUPPORTED
     },
     backdrop: appearanceSetting('window-layout', ['background', 'blur'], 'backdrop'),
+    fileBrowser: appearanceSetting(
+      'window-layout',
+      ['file browser', 'files', 'file tree', 'explorer', 'right sidebar', 'panel', 'startup'],
+      'fileBrowser'
+    ),
     composerPopout: appearanceSetting(
       'window-layout',
       ['composer', 'floating', 'drag', 'popout', 'dock', 'input'],