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.
SdkServiceLevelPublisher writes Server.ServiceLevel through the SDK's
ServerObjectState — the standard OPC UA non-transparent-redundancy signal
clients use to pick a primary. Writes are guarded by DiagnosticsLock so
concurrent SDK diagnostics scans don't fight with our updates.
DeferredServiceLevelPublisher mirrors the DeferredAddressSpaceSink late-
binding pattern: Akka actors resolve IServiceLevelPublisher at construction,
hosted service swaps the SDK publisher in after StandardServer.Start. Host
Program.cs registers DeferredServiceLevelPublisher as the singleton bound
to IServiceLevelPublisher; OtOpcUaServerHostedService gets it injected and
fills it once IServerInternal is available.
Tests boot a real StandardServer on a free port (cross-platform), call
Publish, then verify ServerObject.ServiceLevel.Value reflects the write.
5 new tests; OpcUaServer suite now 45/45 green (was 40, +5).
Closes#81 residual. Unblocks Task 60 (OPC UA dual-endpoint + ServiceLevel
tests).