Adds the decnet clusterer master-only command + provider-subpackage
shape (base.py + factory.py + impl/connected_components.py) so
subsequent commits can land similarity-graph features without
churning callers.
The skeleton ConnectedComponentsClusterer.tick is a no-op; the
worker shell is fully wired (bus consumer on attacker.observed +
attacker.scored, slow-tick fallback, health heartbeat, control
listener, ClusterResult fan-out to identity.formed/observation.linked
/merged). Subscribers on identity.> see no events from this clusterer
until edge functions land, but the lifecycle is in place.
anti
e545f7d8d3