refactor(desktop): keep remote fs routing inside the fs facade

Let UI callers ask for folders/files without knowing remote-picker limits:
selectDesktopPaths now normalizes remote directory selection to a single folder
inside the facade. Project creation and composer context picking no longer branch
on remote mode; they route through desktop-fs helpers just like git callers route
through desktopGit(). Behavior unchanged except remote folder context now works
through the same backend picker path.

apps/desktop/src/app/chat/hooks/use-composer-actions.ts

@@ -5,7 +5,7 @@ import { droppedFileInlineRef } from '@/app/chat/composer/inline-refs'
 import { formatRefValue } from '@/components/assistant-ui/directive-text'
 import { useI18n } from '@/i18n'
 import { attachmentId, contextPath, pathLabel } from '@/lib/chat-runtime'
-import { isDesktopFsRemoteMode, readDesktopFileDataUrl, selectDesktopPaths } from '@/lib/desktop-fs'
+import { readDesktopFileDataUrl, selectDesktopPaths } from '@/lib/desktop-fs'
 import {
   addComposerAttachment,
   type ComposerAttachment,
@@ -266,8 +266,7 @@ export function useComposerActions({ activeSessionId, currentCwd, requestGateway
       const paths = await selectDesktopPaths({
         title: kind === 'file' ? 'Add files as context' : 'Add folders as context',
         defaultPath: currentCwd || undefined,
-        directories: kind === 'folder',
-        multiple: kind === 'folder' && isDesktopFsRemoteMode() ? false : undefined
+        directories: kind === 'folder'
       })
 
       if (!paths?.length) {

apps/desktop/src/lib/desktop-fs.test.ts

@@ -132,15 +132,15 @@ describe('desktop filesystem facade', () => {
     expect(selectPaths).not.toHaveBeenCalled()
   })
 
-  it('does not treat the remote directory picker as a general file picker', async () => {
+  it('limits the remote picker to single-directory selection', async () => {
     const remoteSelect = vi.fn(async () => ['/remote/project'])
     $connection.set({ mode: 'remote' } as never)
     setDesktopFsRemotePicker({ selectPaths: remoteSelect })
 
     await expect(selectDesktopPaths({ directories: false, multiple: false })).resolves.toEqual([])
-    await expect(selectDesktopPaths({ directories: true, multiple: true })).resolves.toEqual([])
+    await expect(selectDesktopPaths({ directories: true })).resolves.toEqual(['/remote/project'])
 
-    expect(remoteSelect).not.toHaveBeenCalled()
+    expect(remoteSelect).toHaveBeenCalledWith({ directories: true, multiple: false })
     expect(selectPaths).not.toHaveBeenCalled()
   })
 })

apps/desktop/src/lib/desktop-fs.ts

@@ -178,9 +178,9 @@ export async function selectDesktopPaths(options?: HermesSelectPathsOptions): Pr
     return desktop.selectPaths(options)
   }
 
-  if (!options?.directories || options.multiple !== false) {
+  if (!options?.directories) {
     return []
   }
 
-  return remotePicker ? remotePicker.selectPaths(options) : []
+  return remotePicker ? remotePicker.selectPaths({ ...options, multiple: false }) : []
 }

apps/desktop/src/store/projects.test.ts

@@ -68,13 +68,12 @@ describe('pickProjectFolder', () => {
     vi.clearAllMocks()
   })
 
-  it('uses the remote-aware directory picker locally (no backend default cwd probe)', async () => {
+  it('uses the remote-aware directory picker locally', async () => {
     isDesktopFsRemoteMode.mockReturnValue(false)
     selectDesktopPaths.mockResolvedValue(['/local/repo'])
 
     await expect(pickProjectFolder()).resolves.toBe('/local/repo')
     expect(selectDesktopPaths).toHaveBeenCalledWith({ defaultPath: undefined, directories: true, multiple: false })
-    expect(desktopDefaultCwd).not.toHaveBeenCalled()
   })
 
   it('seeds the picker with the backend cwd on a remote gateway', async () => {

apps/desktop/src/store/projects.ts

@@ -2,7 +2,7 @@ import { atom } from 'nanostores'
 
 import { liveSessionProjectId, type SidebarProjectTree } from '@/app/chat/sidebar/projects/workspace-groups'
 import type { HermesGitBranch } from '@/global'
-import { desktopDefaultCwd, isDesktopFsRemoteMode, selectDesktopPaths, writeDesktopFileText } from '@/lib/desktop-fs'
+import { desktopDefaultCwd, selectDesktopPaths, writeDesktopFileText } from '@/lib/desktop-fs'
 import { desktopGit } from '@/lib/desktop-git'
 import { persistentAtom } from '@/lib/persisted'
 import { activeGateway, ensureActiveGatewayOpen } from '@/store/gateway'
@@ -282,7 +282,7 @@ export async function fetchProjectSessions(projectId: string): Promise<SidebarPr
 let didScanRepos = false
 
 export async function scanAndRecordRepos(force = false): Promise<void> {
-  const scan = window.hermesDesktop?.git?.scanRepos
+  const scan = desktopGit()?.scanRepos
 
   if (!scan || (didScanRepos && !force)) {
     return
@@ -738,8 +738,11 @@ export async function copyPath(path: null | string): Promise<void> {
 // mode opens the native dialog. Returns the absolute path, or null if cancelled.
 export async function pickProjectFolder(): Promise<null | string> {
   try {
-    const defaultPath = isDesktopFsRemoteMode() ? (await desktopDefaultCwd())?.cwd : undefined
-    const [dir] = await selectDesktopPaths({ defaultPath, directories: true, multiple: false })
+    const [dir] = await selectDesktopPaths({
+      defaultPath: (await desktopDefaultCwd())?.cwd,
+      directories: true,
+      multiple: false
+    })
 
     return dir || null
   } catch {