a5256e9b12
'Pattern 4: Integration Routing' — RouteIntegrationCallAsync → SiteEnvelope(IntegrationCallRequest) → SiteCommunicationActor integration handler — was plumbed end to end but connected at neither end: no producer (zero callers) and no handler (AkkaHostedService never registered LocalHandlerType.Integration). It was an early scaffold the architecture routed around — the brokered External→Central→Site→Central round-trip is served by the Inbound API's routed-site-script path (the RouteTo* verbs, driven from CommunicationServiceInstanceRouter), which is live, tested, and shares IntegrationTimeout. Decision (#32): delete. Removed the IntegrationCall{Request,Response} messages, RouteIntegrationCallAsync, the SiteCommunicationActor receive block + _integrationHandler field + LocalHandlerType.Integration, and the four tests that covered them (2 actor, 2 message-contract, 1 dispatcher- reject, 1 mapper-reject). KEPT IntegrationTimeout — it is the live timeout for the RouteTo* verbs. Updated the exclusion-narrative comments (proto/mapper/dispatcher), design §4, the components doc timeout table, and marked the known-issue RESOLVED. Full solution build clean (0/0); Communication 634 + Host 421 green. Net -172/+20 across 14 files. Not in the gRPC proto (was deliberately excluded there), so no wire-format change.