Adds "NodeName" to the ScadaLink:Node section of each per-node appsettings: - central-a, central-b for the two central nodes - node-a, node-b under each of the three sites (site-a, site-b, site-c) After this commit + a redeploy, every fresh AuditLog / Notifications / SiteCalls row gets stamped with the originating node's role name via INodeIdentityProvider, satisfying the design's SourceNode invariant end-to-end.