Union workspaces for the dsh web GUI: merge multiple directories into one session (primary + members), persist them under ~/.dsh/union-workspaces.json, apply a permission preset per union, browse member files in a right-side panel, and manage everything from a settings section and the /uw command. Hot-pluggable — mounted via ~/.dsh/cordis.patch.yml + a profile node_modules link, no dsh source changes.