Add SiteReplicationActor (runs on every site node) to replicate deployed
configs and store-and-forward buffer operations to the standby peer via
cluster member discovery and fire-and-forget Tell. Wire ReplicationService
handler and pass replication actor to DeploymentManagerActor singleton.
Fix 5 pre-existing ConfigurationDatabase test failures: RowVersion NOT NULL
on SQLite, stale migration name assertion, and seed data count mismatch.
DeploymentManagerActor now handles SubscribeDebugViewRequest and
UnsubscribeDebugViewRequest by forwarding to the appropriate Instance Actor.
This completes the debug view data flow from Central UI through to the site's
Instance Actor snapshot. Reduced refresh interval to 2s for responsiveness.
