R1.1 ExecuteSqlCommandAsync (ExeC + GetR, NRBF DataTable, no BinaryFormatter)

Ship SQL command execution over the 2020 WCF aa/Retr/ExeC + aa/Retr/GetR ops:
HistorianClient.ExecuteSqlCommandAsync(sql) -> HistorianSqlResult (columns +
typed rows). String-handle ops reached with the Open2 storage-session GUID
formatted uppercase (the handle format that unlocked GETRP/GETHI).

Chain: Retr.GetV prime -> ExeC(handle, sql, option=0, ref queryHandle) ->
GetR loop. Key gotcha captured: GetR returns FALSE even on success -- the byte
stream is in pResultBuff regardless; false just signals the final page. So the
orchestrator consumes the buffer first, then stops on a false result / empty page.

GetR's pResultBuff is an NRBF-serialized System.Data.DataTable
(SerializationFormat.Xml: members XmlSchema (XSD) + XmlDiffGram (rows)).
BinaryFormatter is removed from .NET 10, so the stream is decoded read-only with
the System.Formats.Nrbf package (NrbfDecoder) + XDocument -- no BinaryFormatter,
no code execution. Values are typed per the XSD type, falling back to string.

Adds: HistorianSqlResult / HistorianSqlColumn / HistorianSqlExecuteOption models,
HistorianSqlResultProtocol (NRBF + diffgram parser), HistorianWcfSqlClient
(ExeC/GetR orchestration with an AVEVA_HISTORIAN_SQL_DUMP diagnostic), dialect +
public API. Golden WcfSqlResultProtocolTests pinned to the real clean GetR stream
for the benign "SELECT 1 AS ProbeValue" (no sensitive data); gated live tests
(single cell + multi-column/multi-row/NULL). Doc: wcf-exec-sql.md; roadmap R1.1
DONE; wall doc + memory updated (incl. the QTB-server-side nuance). 229 tests green.

Note: a raw instrument-wcf capture corrupts a large pResultBuff with MDAS
transport chunk markers (0x9F); the clean contract-level byte[] is dumped via the
AVEVA_HISTORIAN_SQL_DUMP env var for the golden fixture.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B6mcaT2PjRFKcogzp9UkfC

tests/AVEVA.Historian.Client.Tests/HistorianClientIntegrationTests.cs

@@ -296,6 +296,65 @@ public sealed class HistorianClientIntegrationTests
         Assert.False(string.IsNullOrWhiteSpace(value));
     }
 
+    [Fact]
+    public async Task ExecuteSqlCommandAsync_AgainstLocalHistorian_ReturnsRecordSet()
+    {
+        string? host = Environment.GetEnvironmentVariable("HISTORIAN_HOST");
+        if (string.IsNullOrWhiteSpace(host) || !string.Equals(host, "localhost", StringComparison.OrdinalIgnoreCase) || !OperatingSystem.IsWindows())
+        {
+            return;
+        }
+
+        HistorianClient client = new(new HistorianClientOptions
+        {
+            Host = host,
+            IntegratedSecurity = true,
+            Transport = HistorianTransport.LocalPipe
+        });
+
+        // ExeC/GetR ride the storage-session GUID as an uppercase string handle. A constant SELECT
+        // returns a single int column; the DataTable is decoded from the NRBF stream (no BinaryFormatter).
+        AVEVA.Historian.Client.Models.HistorianSqlResult result =
+            await client.ExecuteSqlCommandAsync("SELECT 1 AS ProbeValue", cancellationToken: CancellationToken.None);
+
+        AVEVA.Historian.Client.Models.HistorianSqlColumn column = Assert.Single(result.Columns);
+        Assert.Equal("ProbeValue", column.Name);
+        IReadOnlyList<object?> row = Assert.Single(result.Rows);
+        Assert.Equal(1, Assert.Single(row));
+    }
+
+    [Fact]
+    public async Task ExecuteSqlCommandAsync_AgainstLocalHistorian_MultiColumnMultiRow()
+    {
+        string? host = Environment.GetEnvironmentVariable("HISTORIAN_HOST");
+        if (string.IsNullOrWhiteSpace(host) || !string.Equals(host, "localhost", StringComparison.OrdinalIgnoreCase) || !OperatingSystem.IsWindows())
+        {
+            return;
+        }
+
+        HistorianClient client = new(new HistorianClientOptions
+        {
+            Host = host,
+            IntegratedSecurity = true,
+            Transport = HistorianTransport.LocalPipe
+        });
+
+        // Fully synthetic query (no server data): two columns (int + string), two rows, one NULL —
+        // exercises the schema/diffgram parser beyond the single-cell case.
+        AVEVA.Historian.Client.Models.HistorianSqlResult result = await client.ExecuteSqlCommandAsync(
+            "SELECT 10 AS Num, 'alpha' AS Word UNION ALL SELECT 20, NULL",
+            cancellationToken: CancellationToken.None);
+
+        Assert.Equal(2, result.Columns.Count);
+        Assert.Equal("Num", result.Columns[0].Name);
+        Assert.Equal("Word", result.Columns[1].Name);
+        Assert.Equal(2, result.Rows.Count);
+        Assert.Equal(10, result.Rows[0][0]);
+        Assert.Equal("alpha", result.Rows[0][1]);
+        Assert.Equal(20, result.Rows[1][0]);
+        Assert.Null(result.Rows[1][1]);
+    }
+
     [Fact]
     public async Task GetConnectionStatusAsync_AgainstLocalHistorian_ReportsConnectedToServer()
     {