Resolve all high-severity architecture review findings

src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Scripts/AuditingDbConnection.cs

@@ -17,8 +17,9 @@ namespace ZB.MOM.WW.ScadaBridge.SiteRuntime.Scripts;
 /// </summary>
 /// <remarks>
 /// <para>
-/// All other <see cref="DbConnection"/> members forward to the inner connection
-/// unchanged so the script keeps full ADO.NET semantics (transactions, state
+/// Transactions and command connection readback retain this wrapper so they cannot
+/// expose an unaudited provider connection. Other members forward to the inner connection
+/// so the script keeps full ADO.NET semantics (transactions, state
 /// transitions, server-version queries, etc.). Disposing the wrapper disposes
 /// the inner connection — the caller is still responsible for disposal per
 /// the <see cref="IDatabaseGateway"/> contract.
@@ -147,7 +148,13 @@ internal sealed class AuditingDbConnection : DbConnection
 
     /// <inheritdoc />
     protected override DbTransaction BeginDbTransaction(IsolationLevel isolationLevel)
-        => _inner.BeginTransaction(isolationLevel);
+        => new AuditingDbTransaction(_inner.BeginTransaction(isolationLevel), this);
+
+    /// <inheritdoc />
+    protected override async ValueTask<DbTransaction> BeginDbTransactionAsync(
+        IsolationLevel isolationLevel, CancellationToken cancellationToken)
+        => new AuditingDbTransaction(
+            await _inner.BeginTransactionAsync(isolationLevel, cancellationToken).ConfigureAwait(false), this);
 
     /// <inheritdoc />
     protected override DbCommand CreateDbCommand()
@@ -168,7 +175,7 @@ internal sealed class AuditingDbConnection : DbConnection
             // threaded alongside _executionId. Null for non-routed runs.
             _parentExecutionId,
             // Flow Debugger: the DbWrite rows ride the inline collector.
-            _onAudit);
+            _onAudit) { Connection = this };
     }
 
     /// <inheritdoc />