Feature Request: Listing Sub-Labels In Label Search Results

It would be nice to have a selectable option in the config for including sub-folders in the search.

For example, if I have a folder heirarchy of:

- Stephen King Books
- Night Shift
- The Stand
- Carrie
- The Shining

If I were to search for "king", having quickmove display not only the resulting search hit of the parent folder, but the folders beneath it would be great. A previous program I used (Postbox) had this functionality in its move-to-folder feature, which I found very convenient. A config switch allowing either behavior would prevent this feature from being too disruptive to those who don't want it.

No files, tests, or entry points are named. Start by locating the folder-search and move-to-folder UI, then trace where add-on configuration is defined and read. Done means a selectable setting controls whether matching parent folders include their subfolders, while preserving the existing behavior when disabled.

Written by the indexing model from the issue text.