fix(config-db): EnableRetryOnFailure fleet-wide + execution-strategy wrap of the combined-telemetry dual-write

Installs SqlServerRetryingExecutionStrategy (5 retries, 30s cap) so transient SQL
faults retry transparently on every read-side path. Manual transactions aren't
auto-retried, so AuditLogIngestActor's idempotent dual-write is wrapped in an
explicit CreateExecutionStrategy().ExecuteAsync to become retriable. Verified
empirically that existing manual transactions (BundleImporter) are unaffected —
EF skips the strategy while a transaction is already active.

tests/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Tests/ServiceCollectionExtensionsTests.cs

@@ -1,4 +1,5 @@
 using System.Reflection;
+using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories;
 using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
@@ -13,7 +14,7 @@ public class ServiceCollectionExtensionsTests
     {
         var services = new ServiceCollection();
 
-        services.AddConfigurationDatabase("DataSource=:memory:");
+        services.AddConfigurationDatabase("Server=unused;Database=unused;");
 
         Assert.Contains(services, d => d.ServiceType == typeof(ITemplateEngineRepository));
         Assert.Contains(services, d => d.ServiceType == typeof(IAuditService));
@@ -21,6 +22,32 @@ public class ServiceCollectionExtensionsTests
         Assert.Contains(services, d => d.ServiceType == typeof(IAuditLogRepository));
     }
 
+    [Fact]
+    public void AddConfigurationDatabase_Configures_RetryingExecutionStrategy()
+    {
+        // Task 12 (arch-review 04 S5): the central DbContext must survive transient
+        // SQL faults. EnableRetryOnFailure installs a non-null ExecutionStrategyFactory
+        // on the SqlServer options extension — covering every read-side path (KPI asks,
+        // outbox queries, Tracking.Status, execution trees) that previously surfaced
+        // transient faults raw.
+        var services = new ServiceCollection();
+        services.AddConfigurationDatabase("Server=unused;Database=unused;");
+        using var sp = services.BuildServiceProvider();
+
+        var options = sp.GetRequiredService<DbContextOptions<ScadaBridgeDbContext>>();
+
+        // EF1001: SqlServerOptionsExtension is an internal EF surface, but it is the
+        // only place the retrying-strategy factory is observable — asserting it is the
+        // point of this test. Scoped suppression, not a project-wide one.
+#pragma warning disable EF1001
+        var sqlExt = options.Extensions
+            .OfType<Microsoft.EntityFrameworkCore.SqlServer.Infrastructure.Internal.SqlServerOptionsExtension>()
+            .Single();
+
+        Assert.NotNull(sqlExt.ExecutionStrategyFactory);
+#pragma warning restore EF1001
+    }
+
     // The no-arg overload is [Obsolete(error: true)], so it cannot be referenced directly
     // from source — that is the compile-time guard. Invoke it via reflection to verify the
     // runtime defence-in-depth behaviour.