* feat(web): show hidden directories in workspace browser
Add optional includeHidden param to the machine list-directory RPC so the
WorkspaceBrowser can toggle hidden (dot-prefixed) entries. Default remains
filtered for backward compatibility; the toggle persists via localStorage.
* fix(web): disable show-hidden toggle while directory loading
Prevent overlapping list-directory requests with opposite includeHidden
values; the toggle is now disabled while a directory load is active.
