Review asked why the launcher special-cases one plugin's row. It no
longer does: the four shipped compositions move into the package
(presets/, in files), dsh-agent-presets resolves its own shipped root
and prepends it before configured roots (includeShippedRoot, default
true, opt-out for bare-machinery embedders), and the per-composition
derived patch, its spec, and the dump layer are deleted — profile-boot
and dump-config return to plain layer stacking. The always-load
guarantee now rides the schema default instead of patch ordering, so a
whole-config replacement keeps the shipped set and the squash, reload
freeze, and dump divergence stop being possible.
Gate globs, the web scaffold, and both preset browser lanes drop their
hand-fed shipped roots; the roster e2e keeps asserting configured roots
beside the shipped four against the built lib.
Fixes#2863.
