Review-driven refinements to the scope-grouped plugin list:
- The preset switcher becomes the General-settings selector pill over the
shared Menu primitive instead of a native select, and the preset group
is collapsible like the global one (search still forces both open).
- The session-plugins drawer is removed: rows the presets took over sit
inline in the global list with the preset-provided tag and per-preset
details, since the preset group above already shows those compositions.
- The status dot renders only for a live root fiber, so file-state rows
of an unmounted preset carry their enablement tag alone instead of a
column of grey dots.
- PresetTree reclaims the owning entry's subtree slot: EntryTree's
constructor filed the standing mount under the roster's own Loader row,
so after the first session composed a preset the whole composition
leaked into root loader.entries() as host rows (each preset overwriting
the last). A regression test holds the root entry list identical across
a mount.