feat(site-runtime): CertStoreActor exports trusted certs (thumbprint+DER) for node reconciliation (UA1 groundwork)

src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Management/CertTrustCommands.cs

@@ -82,6 +82,30 @@ public record RemoveCertFromLocalStore(string Thumbprint);
 /// <summary>Per-node: enumerate the local trusted-peer and rejected stores.</summary>
 public record ListLocalCerts();
 
+/// <summary>
+/// Per-node: export the trusted-peer store contents (thumbprint + raw DER bytes)
+/// so the Deployment Manager singleton can reconcile the trusted set onto a
+/// (re)joining site node. Trusted store only — rejected certs are never pushed.
+/// </summary>
+public record ExportLocalTrustedCerts();
+
+/// <summary>
+/// One exported trusted certificate: its thumbprint (store filename key) and the
+/// raw DER bytes needed to re-write it into another node's trusted-peer store.
+/// </summary>
+/// <param name="Thumbprint">The certificate thumbprint.</param>
+/// <param name="DerBytes">The certificate's raw DER encoding.</param>
+public record ExportedCert(string Thumbprint, byte[] DerBytes);
+
+/// <summary>
+/// Per-node reply to <see cref="ExportLocalTrustedCerts"/>: the local trusted-peer
+/// store's certificates, or a failure with the IO error.
+/// </summary>
+/// <param name="Success">True if the trusted store was enumerated successfully.</param>
+/// <param name="Error">The error message on failure, otherwise null.</param>
+/// <param name="Certs">Exported trusted certificates, empty on failure.</param>
+public record LocalCertExport(bool Success, string? Error, IReadOnlyList<ExportedCert> Certs);
+
 /// <summary>
 /// Per-node ack for a <see cref="WriteCertToLocalStore"/>, <see cref="RemoveCertFromLocalStore"/>
 /// or <see cref="ListLocalCerts"/> operation.

src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/CertStoreActor.cs

@@ -51,6 +51,7 @@ public class CertStoreActor : ReceiveActor
         Receive<WriteCertToLocalStore>(HandleWrite);
         Receive<RemoveCertFromLocalStore>(HandleRemove);
         Receive<ListLocalCerts>(_ => HandleList());
+        Receive<ExportLocalTrustedCerts>(_ => HandleExport());
     }
 
     /// <summary>
@@ -133,6 +134,47 @@ public class CertStoreActor : ReceiveActor
         }
     }
 
+    /// <summary>
+    /// Exports the trusted-peer store (thumbprint + raw DER) so the Deployment
+    /// Manager singleton can reconcile the trusted set onto a (re)joining node.
+    /// Trusted store only — rejected certs are never pushed to peers.
+    /// </summary>
+    private void HandleExport()
+    {
+        try
+        {
+            var certs = new List<ExportedCert>();
+            if (Directory.Exists(_trustedStoreDir))
+            {
+                foreach (var file in Directory.EnumerateFiles(_trustedStoreDir)
+                             .Where(f => f.EndsWith(".der", StringComparison.OrdinalIgnoreCase)
+                                         || f.EndsWith(".crt", StringComparison.OrdinalIgnoreCase)))
+                {
+                    try
+                    {
+                        var der = File.ReadAllBytes(file);
+                        // Load only to derive the canonical thumbprint (the store
+                        // filename); the DER bytes shipped are the raw file bytes.
+                        using var cert = X509CertificateLoader.LoadCertificate(der);
+                        certs.Add(new ExportedCert(cert.Thumbprint, der));
+                    }
+                    catch (Exception ex)
+                    {
+                        // A malformed file must not abort the whole export.
+                        _log.Warning(ex, "Skipping unreadable certificate file {File} during export", file);
+                    }
+                }
+            }
+
+            Sender.Tell(new LocalCertExport(true, null, certs));
+        }
+        catch (Exception ex)
+        {
+            _log.Warning(ex, "Failed to export trusted certificates from PKI store");
+            Sender.Tell(new LocalCertExport(false, ex.Message, Array.Empty<ExportedCert>()));
+        }
+    }
+
     private IEnumerable<TrustedCertInfo> EnumerateStore(string storeDir, bool rejected)
     {
         if (!Directory.Exists(storeDir))

tests/ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests/Actors/CertStoreActorTests.cs

@@ -106,6 +106,27 @@ public class CertStoreActorTests : TestKit, IDisposable
         emptyAck.Certs!.Should().NotContain(c => c.Thumbprint == thumbprint);
     }
 
+    [Fact]
+    public void ExportLocalTrustedCerts_ReturnsThumbprintAndDerBytes()
+    {
+        var (derBase64, thumbprint) = BuildSelfSignedCert();
+        var expectedDer = Convert.FromBase64String(derBase64);
+        var actor = Sys.ActorOf(Props.Create(() => new CertStoreActor(_options)));
+
+        // Seed one trusted cert via the normal write path.
+        actor.Tell(new WriteCertToLocalStore(derBase64, thumbprint));
+        ExpectMsg<LocalCertOpAck>().Success.Should().BeTrue();
+
+        // Export — thumbprint + raw DER bytes come back for reconciliation.
+        actor.Tell(new ExportLocalTrustedCerts());
+        var export = ExpectMsg<LocalCertExport>();
+        export.Success.Should().BeTrue();
+        export.Error.Should().BeNull();
+        var entry = export.Certs.Should().ContainSingle().Subject;
+        entry.Thumbprint.Should().Be(thumbprint);
+        entry.DerBytes.Should().Equal(expectedDer);
+    }
+
     [Fact]
     public void Write_InvalidBase64_ReturnsFailureAck()
     {