feat(siteruntime): ExternalSystem.CachedCall emits CachedSubmit telemetry (#23 M3)

Rework ScriptRuntimeContext.ExternalSystem.CachedCall to fit the M3
combined-telemetry model:

* Mints a fresh TrackedOperationId and emits one CachedSubmit packet
  via ICachedCallTelemetryForwarder BEFORE handing the call off — the
  SiteCalls row is materialised before the first delivery attempt so
  Tracking.Status(id) can observe a Submitted row even if immediate
  delivery resolves before the helper returns.
* Threads the TrackedOperationId into IExternalSystemClient.CachedCallAsync
  as a new optional parameter (and into IDatabaseGateway.CachedWriteAsync
  for the Database mirror set up here for E6). The gateway uses the id
  as the StoreAndForward messageId so the retry loop (Tasks E4/E5) can
  recover it from StoreAndForwardMessage.Id.
* Returns the TrackedOperationId rather than ExternalCallResult — the
  script's contract is now "get a tracking handle, observe outcome via
  Tracking.Status". Best-effort emission: a thrown forwarder is logged
  + swallowed; the original call still runs and the id is still returned.

DatabaseHelper gets the matching siteId / sourceScript / forwarder
fields and a parallel CachedSubmit emitter (Channel=DbOutbound) so Task
E6's Database.CachedWrite mirror plugs in without further runtime
wiring.

New ICachedCallTelemetryForwarder seam in Commons.Interfaces.Services
so SiteRuntime depends on Commons (existing arrow) rather than
ScadaLink.AuditLog (would have introduced a new dependency).

Bundle E task E3 (and helper-shape work for E6).

src/ScadaLink.ExternalSystemGateway/DatabaseGateway.cs

@@ -5,6 +5,7 @@ using Microsoft.Extensions.Logging;
 using ScadaLink.Commons.Entities.ExternalSystems;
 using ScadaLink.Commons.Interfaces.Repositories;
 using ScadaLink.Commons.Interfaces.Services;
+using ScadaLink.Commons.Types;
 using ScadaLink.Commons.Types.Enums;
 using ScadaLink.StoreAndForward;
 
@@ -71,12 +72,19 @@ public class DatabaseGateway : IDatabaseGateway
     /// <summary>
     /// Submits a SQL write to the store-and-forward engine for reliable delivery.
     /// </summary>
+    /// <param name="trackedOperationId">
+    /// Audit Log #23 (M3): used as the S&amp;F message id so the retry loop can
+    /// recover it via <c>StoreAndForwardMessage.Id</c> and emit per-attempt /
+    /// terminal cached-write telemetry (Tasks E4/E5). Null preserves the
+    /// pre-M3 behaviour (S&amp;F mints a random GUID).
+    /// </param>
     public async Task CachedWriteAsync(
         string connectionName,
         string sql,
         IReadOnlyDictionary<string, object?>? parameters = null,
         string? originInstanceName = null,
-        CancellationToken cancellationToken = default)
+        CancellationToken cancellationToken = default,
+        TrackedOperationId? trackedOperationId = null)
     {
         var definition = await ResolveConnectionAsync(connectionName, cancellationToken);
         if (definition == null)
@@ -110,7 +118,13 @@ public class DatabaseGateway : IDatabaseGateway
             payload,
             originInstanceName,
             definition.MaxRetries > 0 ? definition.MaxRetries : null,
-            definition.RetryDelay > TimeSpan.Zero ? definition.RetryDelay : null);
+            definition.RetryDelay > TimeSpan.Zero ? definition.RetryDelay : null,
+            // Audit Log #23 (M3): pin the S&F message id to the
+            // TrackedOperationId so the retry loop (Bundle E Tasks E4/E5) can
+            // read it back via StoreAndForwardMessage.Id and emit per-attempt +
+            // terminal cached-write telemetry. Null -> S&F mints its own GUID
+            // (legacy pre-M3 behaviour).
+            messageId: trackedOperationId?.ToString());
     }
 
     /// <summary>