Live test B1: the Folder list indented a server list sorted as full-path
text, so "-" and "_" sorted before "/" and children landed under the wrong
parent (kiko/char under kiko-v6), with case variants interleaved. The
options are now a tree built by segment: each folder directly under its own
parent, case variants distinct siblings.
On POSIX a folder named "Metadata\Klein..." was listed but filtered to no
prompts, because normalize_folder read "\" as a separator. It now does so
only on Windows (ntpath), as the listing already did.
Refs #444
Refine this view on the Prompt library gains the concept's Folder (folders
below an output root, read when the dialog opens) and a Tag match select
(All / Any). The listing takes folder and tag_mode, matches folders on the
normalized file_path under every spelling of each output root, echoes both
so a stale server is an error, and saved Library views keep them. Recorded
as D150.
Refs #444
Vito Sansevero