Expand description
Cocoon → register_scm_resource_group notification.
Pairs with RegisterScmProvider. An SCM provider creates one or more
resource groups (Git’s “Changes”, “Staged Changes”, “Merge Changes”).
Two side effects:
VineHost::UpdateSourceControlGroupseeds the group with an emptyresourceStateslist so subsequentupdate_scm_groupcalls find it.sky://scm/registerGrouprenderer event materialises the group header row in the SCM viewlet.