feat(auditlog): site script-side emitters stamp ExecutionId

Move the per-script-execution Guid on ScriptRuntimeContext from
_auditCorrelationId to _executionId, and stamp it into the dedicated
AuditEvent.ExecutionId column on every script-side audit row:

- Sync ApiCall / DbWrite: ExecutionId set; CorrelationId reverts to
  null (a sync one-shot call has no operation lifecycle).
- Cached-call script-side rows (CachedSubmit, immediate-completion
  ApiCallCached + CachedResolve) and NotifySend: ExecutionId set;
  CorrelationId unchanged (per-operation TrackedOperationId /
  NotificationId).

Renames the threaded ctor param/field across ExternalSystemHelper,
DatabaseHelper, AuditingDbConnection and AuditingDbCommand, and threads
the id through NotifyHelper/NotifyTarget. The S&F retry-loop cached rows
(CachedCallLifecycleBridge) are out of scope here.

tests/ScadaLink.SiteRuntime.Tests/Scripts/ExternalSystemCallAuditEmissionTests.cs

@@ -46,27 +46,27 @@ public class ExternalSystemCallAuditEmissionTests
     private const string SourceScript = "ScriptActor:CheckPressure";
 
     /// <summary>
-    /// Audit Log #23: a fixed execution-wide correlation id used by the
-    /// default <see cref="CreateHelper(IExternalSystemClient, IAuditWriter?)"/>
+    /// Audit Log #23: a fixed per-execution id used by the default
+    /// <see cref="CreateHelper(IExternalSystemClient, IAuditWriter?)"/>
     /// overload so assertions can compare against a known value.
     /// </summary>
-    private static readonly Guid TestCorrelationId = Guid.NewGuid();
+    private static readonly Guid TestExecutionId = Guid.NewGuid();
 
     private static ScriptRuntimeContext.ExternalSystemHelper CreateHelper(
         IExternalSystemClient client,
         IAuditWriter? auditWriter)
-        => CreateHelper(client, auditWriter, TestCorrelationId);
+        => CreateHelper(client, auditWriter, TestExecutionId);
 
     private static ScriptRuntimeContext.ExternalSystemHelper CreateHelper(
         IExternalSystemClient client,
         IAuditWriter? auditWriter,
-        Guid correlationId)
+        Guid executionId)
     {
         return new ScriptRuntimeContext.ExternalSystemHelper(
             client,
             InstanceName,
             NullLogger.Instance,
-            correlationId,
+            executionId,
             auditWriter,
             SiteId,
             SourceScript);
@@ -225,47 +225,54 @@ public class ExternalSystemCallAuditEmissionTests
         Assert.Equal(SourceScript, evt.SourceScript);
         // Outbound channel: Actor carries the calling script identity.
         Assert.Equal(SourceScript, evt.Actor);
-        // Audit Log #23: the sync ApiCall row now carries the execution-wide
-        // correlation id the helper was constructed with.
-        Assert.Equal(TestCorrelationId, evt.CorrelationId);
+        // Audit Log #23: the sync ApiCall row carries the per-execution id the
+        // helper was constructed with in ExecutionId. CorrelationId is null —
+        // a sync one-shot call has no operation lifecycle.
+        Assert.Equal(TestExecutionId, evt.ExecutionId);
+        Assert.Null(evt.CorrelationId);
     }
 
     [Fact]
-    public async Task Call_SyncApiCall_StampsExecutionCorrelationId()
+    public async Task Call_SyncApiCall_StampsExecutionId_AndNullCorrelationId()
     {
         var client = new Mock<IExternalSystemClient>();
         client
             .Setup(c => c.CallAsync("ERP", "GetOrder", It.IsAny<IReadOnlyDictionary<string, object?>?>(), It.IsAny<CancellationToken>()))
             .ReturnsAsync(new ExternalCallResult(true, "{}", null));
         var writer = new CapturingAuditWriter();
-        var correlationId = Guid.NewGuid();
+        var executionId = Guid.NewGuid();
 
-        var helper = CreateHelper(client.Object, writer, correlationId);
+        var helper = CreateHelper(client.Object, writer, executionId);
         await helper.Call("ERP", "GetOrder");
 
         var evt = Assert.Single(writer.Events);
-        Assert.Equal(correlationId, evt.CorrelationId);
+        Assert.Equal(executionId, evt.ExecutionId);
+        // Sync one-shot call: CorrelationId is null (no operation lifecycle).
+        Assert.Null(evt.CorrelationId);
     }
 
     [Fact]
-    public async Task Call_TwoCallsOnSameHelper_ShareTheSameCorrelationId()
+    public async Task Call_TwoCallsOnSameHelper_ShareTheSameExecutionId()
     {
         var client = new Mock<IExternalSystemClient>();
         client
             .Setup(c => c.CallAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<IReadOnlyDictionary<string, object?>?>(), It.IsAny<CancellationToken>()))
             .ReturnsAsync(new ExternalCallResult(true, "{}", null));
         var writer = new CapturingAuditWriter();
-        var correlationId = Guid.NewGuid();
+        var executionId = Guid.NewGuid();
 
-        var helper = CreateHelper(client.Object, writer, correlationId);
+        var helper = CreateHelper(client.Object, writer, executionId);
         await helper.Call("ERP", "GetOrder");
         await helper.Call("ERP", "GetCustomer");
 
         Assert.Equal(2, writer.Events.Count);
-        // Both sync ApiCall rows from one execution carry the same id.
-        Assert.Equal(correlationId, writer.Events[0].CorrelationId);
-        Assert.Equal(correlationId, writer.Events[1].CorrelationId);
-        Assert.Equal(writer.Events[0].CorrelationId, writer.Events[1].CorrelationId);
+        // Both sync ApiCall rows from one execution carry the same ExecutionId.
+        Assert.Equal(executionId, writer.Events[0].ExecutionId);
+        Assert.Equal(executionId, writer.Events[1].ExecutionId);
+        Assert.Equal(writer.Events[0].ExecutionId, writer.Events[1].ExecutionId);
+        // Neither sync call carries a CorrelationId.
+        Assert.Null(writer.Events[0].CorrelationId);
+        Assert.Null(writer.Events[1].CorrelationId);
     }
 
     [Fact]