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.

src/ScadaLink.SiteRuntime/Scripts/AuditingDbCommand.cs

@@ -37,11 +37,11 @@ internal sealed class AuditingDbCommand : DbCommand
     private readonly string _siteId;
     private readonly string _instanceName;
     private readonly string? _sourceScript;
-    private readonly Guid _auditCorrelationId;
+    private readonly Guid _executionId;
     private readonly ILogger _logger;
     private DbConnection? _wrappingConnection;
 
-    // Parameter ordering: auditCorrelationId sits immediately after the ILogger,
+    // Parameter ordering: executionId sits immediately after the ILogger,
     // consistent with the other three audit-threaded ctors (ExternalSystemHelper,
     // DatabaseHelper, AuditingDbConnection).
     public AuditingDbCommand(
@@ -52,7 +52,7 @@ internal sealed class AuditingDbCommand : DbCommand
         string instanceName,
         string? sourceScript,
         ILogger logger,
-        Guid auditCorrelationId)
+        Guid executionId)
     {
         _inner = inner ?? throw new ArgumentNullException(nameof(inner));
         _auditWriter = auditWriter ?? throw new ArgumentNullException(nameof(auditWriter));
@@ -61,7 +61,7 @@ internal sealed class AuditingDbCommand : DbCommand
         _instanceName = instanceName ?? string.Empty;
         _sourceScript = sourceScript;
         _logger = logger ?? throw new ArgumentNullException(nameof(logger));
-        _auditCorrelationId = auditCorrelationId;
+        _executionId = executionId;
     }
 
     // -- Forwarded surface ------------------------------------------------
@@ -432,10 +432,12 @@ internal sealed class AuditingDbCommand : DbCommand
             OccurredAtUtc = DateTime.SpecifyKind(occurredAtUtc, DateTimeKind.Utc),
             Channel = AuditChannel.DbOutbound,
             Kind = AuditKind.DbWrite,
-            // Audit Log #23: the execution-wide correlation id, so this sync
-            // DbWrite row shares an id with the other sync trust-boundary rows
-            // from the same script run.
-            CorrelationId = _auditCorrelationId,
+            // Audit Log #23: a sync one-shot DB write has no operation
+            // lifecycle, so CorrelationId is null. ExecutionId carries the
+            // per-execution id so this row shares an id with the other sync
+            // trust-boundary rows from the same script run.
+            CorrelationId = null,
+            ExecutionId = _executionId,
             SourceSiteId = string.IsNullOrEmpty(_siteId) ? null : _siteId,
             SourceInstanceId = _instanceName,
             SourceScript = _sourceScript,