pub async fn pick_output_dir(app: AppHandle) -> Result<Option<String>, String>Expand description
Open a native folder picker and return the chosen absolute path,
or None if the user cancelled. Does not persist the choice —
the caller (set_output_dir) does. Opens at the current
configured directory when it exists.
Runs on the blocking thread pool via spawn_blocking: the
dialog-plugin blocking_* variants block the calling thread until
the user responds, and deadlock if that’s the main thread.
§Errors
Errors only if the dialog task fails to join; a user cancel is
Ok(None).