canon: distinguish sector domains from project identity

canon/standards/contribution-convention_v0.1.md

@@ -65,7 +65,7 @@ target_org: <github-org-or-owner>                  # required
 target_repo: <repository-name>                     # required
 title: "Human-readable title"                      # required
 status: draft | submitted | acknowledged | accepted | rejected | merged | withdrawn
-domain: custodian | railiance | markitect | ...    # originating domain
+domain: infotech | agents | communication | ...   # current sector domain; see Repo Classification Standard §6
 related_workstream: <workstream-slug>              # optional
 state_hub_contribution_id: <uuid>                  # set once registered in State Hub
 created: "YYYY-MM-DD"