R0.6: fail-closed server interface-version gate at connect

Turns the previously-discarded GetInterfaceVersion result into a connect-time
version pin. The native buffers carried in the WCF/MDAS body (and in the 2023 R2
gRPC bytes fields) are framed per native interface version; parsing them against
an unexpected version risks silent misinterpretation, so we throw rather than
best-effort parse.

- HistorianServerVersionGate + HistorianServiceInterface: evidence-based
  supported versions discovered from a live Historian 2020 server (product
  20.0.000) via the wcf-probe command — History=11, Retrieval=4, Transaction=2.
  Status' GetInterfaceVersion returns 0, so Status is reachability-only.
- HistorianClientOptions.VerifyServerInterfaceVersion (default true) — bypass
  knob for bringing up a server whose reported integers aren't yet captured
  (e.g. a 2023 R2 gRPC endpoint carrying the same proven 2020 buffers).
- Wired into both transports' connect paths: WCF history (auth-chain helper) +
  retrieval (read orchestrator), and gRPC history + retrieval.
- Mismatch throws ProtocolEvidenceMissingException naming reported/expected
  version and the bypass knob.

10 new unit tests (198 total green). Verified the gate does not regress the
proven WCF read path: a live read against the local 2020 server reaches past the
gate (Retr=4 matches) — the only live failures are a pre-existing environmental
read timeout (OperationCanceledException), identical with and without this change.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/AVEVA.Historian.Client/Grpc/HistorianGrpcReadOrchestrator.cs

@@ -163,7 +163,9 @@ internal sealed class HistorianGrpcReadOrchestrator
         Guid contextKey = Guid.NewGuid();
         var historyClient = new GrpcHistory.HistoryService.HistoryServiceClient(connection.Channel);
 
-        historyClient.GetInterfaceVersion(new GrpcHistory.GetInterfaceVersionRequest(), connection.Metadata, Deadline(), cancellationToken);
+        GrpcHistory.GetInterfaceVersionResponse historyVersion = historyClient.GetInterfaceVersion(
+            new GrpcHistory.GetInterfaceVersionRequest(), connection.Metadata, Deadline(), cancellationToken);
+        HistorianServerVersionGate.Validate(HistorianServiceInterface.History, historyVersion.UiVersion, _options);
 
         HistorianNativeHandshake.RunTokenRounds(
             (handle, wrapped, _) =>
@@ -210,7 +212,9 @@ internal sealed class HistorianGrpcReadOrchestrator
         CancellationToken cancellationToken)
     {
         var retrievalClient = new GrpcRetrieval.RetrievalService.RetrievalServiceClient(connection.Channel);
-        retrievalClient.GetRetrievalInterfaceVersion(new GrpcRetrieval.GetRetrievalInterfaceVersionRequest(), null, Deadline(), cancellationToken);
+        GrpcRetrieval.GetRetrievalInterfaceVersionResponse retrievalVersion = retrievalClient.GetRetrievalInterfaceVersion(
+            new GrpcRetrieval.GetRetrievalInterfaceVersionRequest(), null, Deadline(), cancellationToken);
+        HistorianServerVersionGate.Validate(HistorianServiceInterface.Retrieval, retrievalVersion.UiVersion, _options);
 
         byte[] requestBuffer = HistorianDataQueryProtocol.SerializeFullHistoryRequest(request);
         uint queryHandle = StartQuery(retrievalClient, clientHandle, requestBuffer, "raw", cancellationToken);
@@ -260,7 +264,9 @@ internal sealed class HistorianGrpcReadOrchestrator
         CancellationToken cancellationToken)
     {
         var retrievalClient = new GrpcRetrieval.RetrievalService.RetrievalServiceClient(connection.Channel);
-        retrievalClient.GetRetrievalInterfaceVersion(new GrpcRetrieval.GetRetrievalInterfaceVersionRequest(), null, Deadline(), cancellationToken);
+        GrpcRetrieval.GetRetrievalInterfaceVersionResponse retrievalVersion = retrievalClient.GetRetrievalInterfaceVersion(
+            new GrpcRetrieval.GetRetrievalInterfaceVersionRequest(), null, Deadline(), cancellationToken);
+        HistorianServerVersionGate.Validate(HistorianServiceInterface.Retrieval, retrievalVersion.UiVersion, _options);
 
         HistorianDataQueryRequest request = HistorianWcfReadOrchestrator.BuildAggregateQueryRequest(tag, startUtc, endUtc, mode, interval);
         byte[] requestBuffer = HistorianDataQueryProtocol.SerializeFullHistoryRequest(request);