Phase 6 (per-cluster mesh split) needs nodes to carry a cluster-scoped
role like cluster-SITE-A; RoleParser previously rejected anything
outside the fixed admin/driver/dev set. Adds IsClusterRole/
ClusterIdFromRole plus well-known-role constants, and points the three
duplicate "driver" string literals (RedundancyStateActor,
ClusterNodeAddressReconcilerActor, ServiceCollectionExtensions) at the
new RoleParser.Driver so the value has one source, without renaming
any existing DriverRole symbol.
Claude-Session: https://claude.ai/code/session_01GASWkNEi68FSCtvr6rLoEW
Adds <summary>, <param>, <typeparam>, and <inheritdoc/> tags to public
members surfaced by commentchecker — resolves 5,847 of 5,869 issues
(99.6%) across three /fixdocs passes.
Joseph Doherty