fix(audit): trace/outbound fault continuations run on the default scheduler and central emitters log (arch-review F8)

Claude-Session: https://claude.ai/code/session_01NcMG6xXdsJbmD2wYAgkK29

src/ZB.MOM.WW.ScadaBridge.InboundAPI/InboundDatabaseHelper.cs

@@ -2,6 +2,7 @@ using System.Data.Common;
 using System.Diagnostics;
 using System.Globalization;
 using System.Text;
+using Microsoft.Extensions.Logging;
 using ZB.MOM.WW.Audit;
 using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Audit;
@@ -70,6 +71,7 @@ public sealed class InboundDatabaseHelper
     private readonly Guid? _parentExecutionId;
     private readonly string? _actor;
     private readonly Action<AuditEvent>? _traceSink;
+    private readonly ILogger? _logger;
 
     /// <summary>
     /// Initializes the helper.
@@ -83,6 +85,7 @@ public sealed class InboundDatabaseHelper
     /// <param name="parentExecutionId">The spawning execution's id, if any (an inbound request is a root, so callers normally pass null).</param>
     /// <param name="methodName">The executing API method's name; the row's <c>Actor</c> becomes <c>api:{methodName}</c>. Null = NULL actor.</param>
     /// <param name="traceSink">Flow Debugger trace sink; receives the same event instance before the writer does. Null = none.</param>
+    /// <param name="logger">Arch-review F8: logs a Warning when the best-effort audit write faults; null = silent.</param>
     // Trailing optional parameters: the original (gateway, ct, commandTimeout) shape stays
     // source-compatible for every existing caller and test.
     public InboundDatabaseHelper(
@@ -94,7 +97,8 @@ public sealed class InboundDatabaseHelper
         Guid? executionId = null,
         Guid? parentExecutionId = null,
         string? methodName = null,
-        Action<AuditEvent>? traceSink = null)
+        Action<AuditEvent>? traceSink = null,
+        ILogger? logger = null)
     {
         _gateway = gateway;
         _ct = ct;
@@ -107,6 +111,7 @@ public sealed class InboundDatabaseHelper
         _parentExecutionId = parentExecutionId;
         _actor = string.IsNullOrEmpty(methodName) ? null : "api:" + methodName;
         _traceSink = traceSink;
+        _logger = logger;
     }
 
     /// <summary>First column of the first row converted to <typeparamref name="T"/> (default if no rows).</summary>
@@ -268,7 +273,11 @@ public sealed class InboundDatabaseHelper
             var t = _auditWriter.WriteAsync(evt, CancellationToken.None);
             if (!t.IsCompletedSuccessfully)
             {
-                _ = t.ContinueWith(static _ => { }, TaskContinuationOptions.OnlyOnFaulted);
+                _ = t.ContinueWith(
+                    x => _logger?.LogWarning(x.Exception, "Flow trace DbOutbound write failed for {Connection}", connectionName),
+                    CancellationToken.None,
+                    TaskContinuationOptions.OnlyOnFaulted | TaskContinuationOptions.ExecuteSynchronously,
+                    TaskScheduler.Default);
             }
         }
         catch (Exception)