fix(host): dev site seed no longer targets the metrics port; validator rejects seed-vs-MetricsPort

src/ZB.MOM.WW.ScadaBridge.Host/StartupValidator.cs

@@ -124,6 +124,14 @@ public static class StartupValidator
                         _ => SeedNodePort(seed) != grpcPort,
                         $"entry '{seed}' must not target the gRPC port " +
                         $"({grpcPort}); seed nodes must reference Akka remoting ports");
+
+                    // Same failure mode as the gRPC guard: the Kestrel HTTP/1.1
+                    // metrics listener is not an Akka.Remote endpoint, so a seed on
+                    // it dials a doomed association forever.
+                    p.Require("ScadaBridge:Cluster:SeedNodes",
+                        _ => SeedNodePort(seed) != metricsPort,
+                        $"entry '{seed}' must not target the metrics port " +
+                        $"({metricsPort}); seed nodes must reference Akka remoting ports");
                 }
             })
             .ThrowIfInvalid();

src/ZB.MOM.WW.ScadaBridge.Host/appsettings.Site.json

@@ -11,9 +11,10 @@
       "NodeName": "node-a"
     },
     "Cluster": {
+      "_seedNodes": "Host-0xx: second entry is the FUTURE node-b remoting port (8085) for a two-node localhost site. It must be an Akka remoting endpoint — never this node's GrpcPort (8083) or MetricsPort (8084); StartupValidator rejects both.",
       "SeedNodes": [
         "akka.tcp://scadabridge@localhost:8082",
-        "akka.tcp://scadabridge@localhost:8084"
+        "akka.tcp://scadabridge@localhost:8085"
       ],
       "SplitBrainResolverStrategy": "keep-oldest",
       "StableAfter": "00:00:15",

tests/ZB.MOM.WW.ScadaBridge.Host.Tests/StartupValidatorTests.cs

@@ -319,6 +319,36 @@ public class StartupValidatorTests
         Assert.Contains("must not target the gRPC port", ex.Message);
     }
 
+    [Fact]
+    public void Site_SeedNodeOnMetricsPort_FailsValidation()
+    {
+        // Review 01 [Medium]: appsettings.Site.json shipped a seed pointing at the
+        // Kestrel HTTP/1.1 metrics listener (8084) — a doomed Akka.Remote
+        // association. The validator guarded GrpcPort but not MetricsPort.
+        var values = ValidSiteConfig();
+        values["ScadaBridge:Node:GrpcPort"] = "8083";
+        values["ScadaBridge:Node:MetricsPort"] = "8084";
+        values["ScadaBridge:Cluster:SeedNodes:1"] = "akka.tcp://scadabridge@site-a-node1:8084";
+        var config = BuildConfig(values);
+
+        var ex = Assert.Throws<InvalidOperationException>(() => StartupValidator.Validate(config));
+        Assert.Contains("must not target the metrics port", ex.Message);
+    }
+
+    [Fact]
+    public void Site_SeedNodeOnDefaultMetricsPort_FailsValidation()
+    {
+        // MetricsPort absent => NodeOptions default 8084. A seed on 8084 must
+        // still be rejected. Keep GrpcPort distinct so only the metrics rule fires.
+        var values = ValidSiteConfig();
+        values["ScadaBridge:Node:GrpcPort"] = "8083";
+        values["ScadaBridge:Cluster:SeedNodes:1"] = "akka.tcp://scadabridge@site-a-node2:8084";
+        var config = BuildConfig(values);
+
+        var ex = Assert.Throws<InvalidOperationException>(() => StartupValidator.Validate(config));
+        Assert.Contains("must not target the metrics port", ex.Message);
+    }
+
     [Fact]
     public void Site_SeedNodeOnDefaultGrpcPort_FailsValidation()
     {