Completes the Inbound API → site script call chain by adding RouteToCallRequest
handlers in SiteCommunicationActor and DeploymentManagerActor. Also replaces the
placeholder dispatch table in InboundScriptExecutor with Roslyn compilation of
API method scripts at startup, enabling user-defined inbound API methods to call
instance scripts across the cluster.
Adds `debug snapshot --id <int>` to query a running instance's current
attribute values and alarm states without the subscribe/stream overhead
of the debug view. Routes through ManagementActor → CommunicationService
→ site DeploymentManager → InstanceActor using the existing remote query
pattern.
Central and site clusters now communicate via ClusterClient/
ClusterClientReceptionist instead of direct ActorSelection. Both
CentralCommunicationActor and SiteCommunicationActor are registered
with their cluster's receptionist. Central creates one ClusterClient
per site using NodeA/NodeB contact points from the DB. Sites configure
multiple CentralContactPoints for automatic failover between central
nodes. ISiteClientFactory enables test injection.