fix(adminui): S7 typed page no longer wipes Tags on save

- S7DriverPage.FormModel now preserves Tags through Form ↔ Options
  translation (was hard-coding Tags = [] on every save, silently
  destroying any tag list that operators had configured).
- Add FormModel_RoundTrip tests for OpcUaClient and Historian
  mirror classes — both were translating Options ↔ form-model
  entirely untested.
- Surface S7 Tags in the round-trip test so this regression
  can't reach merge again.

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/Clusters/Drivers/S7DriverPage.razor

@@ -300,6 +300,9 @@ else
         // Tags JSON view (read-only)
         public string? TagsJson { get; set; }
 
+        // Preserved originals (round-tripped unchanged from original options)
+        private IReadOnlyList<S7TagDefinition> _tags = [];
+
         // Common
         public string? ResilienceConfig { get; set; }
         public byte[] RowVersion { get; set; } = [];
@@ -326,6 +329,7 @@ else
                 ProbeTimeoutSeconds = (int)o.Probe.Timeout.TotalSeconds,
                 AdminProbeTimeoutSeconds = o.ProbeTimeoutSeconds,
                 TagsJson = tagsJson,
+                _tags = o.Tags,
             };
         }
 
@@ -344,8 +348,7 @@ else
                 Timeout = TimeSpan.FromSeconds(ProbeTimeoutSeconds),
             },
             ProbeTimeoutSeconds = AdminProbeTimeoutSeconds,
-            // Tags preserved from original JSON; this form does not edit the tag list.
+            Tags = _tags,
-            Tags = [],
         };
     }
 }

tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/HistorianWonderwareDriverPageFormSerializationTests.cs

@@ -2,6 +2,7 @@ using System.Text.Json;
 using System.Text.Json.Serialization;
 using Shouldly;
 using Xunit;
+using ZB.MOM.WW.OtOpcUa.AdminUI.Components.Pages.Clusters.Drivers;
 using ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware.Client;
 
 namespace ZB.MOM.WW.OtOpcUa.AdminUI.Tests;
@@ -80,4 +81,32 @@ public sealed class HistorianWonderwareDriverPageFormSerializationTests
         back.ProbeTimeoutSeconds.ShouldBe(20);
         back.PipeName.ShouldBe("otopcua-historian");
     }
+
+    [Fact]
+    public void FormModel_RoundTrip_PreservesAllFields()
+    {
+        // Construct a record with non-default values for every property and verify
+        // that WonderwareHistorianClientFormModel.FromRecord → ToRecord is lossless.
+        var original = new WonderwareHistorianClientOptions(
+            PipeName: "otopcua-historian-prod",
+            SharedSecret: "sup3rs3cr3t",
+            PeerName: "OtOpcUa-Redundant",
+            ConnectTimeout: TimeSpan.FromSeconds(18),
+            CallTimeout: TimeSpan.FromSeconds(45))
+        {
+            ProbeTimeoutSeconds = 30,
+        };
+
+        var form = HistorianWonderwareDriverPage.WonderwareHistorianClientFormModel.FromRecord(original);
+        var result = form.ToRecord();
+
+        result.PipeName.ShouldBe("otopcua-historian-prod");
+        result.SharedSecret.ShouldBe("sup3rs3cr3t");
+        result.PeerName.ShouldBe("OtOpcUa-Redundant");
+        result.ConnectTimeout.ShouldBe(TimeSpan.FromSeconds(18));
+        result.CallTimeout.ShouldBe(TimeSpan.FromSeconds(45));
+        result.EffectiveConnectTimeout.ShouldBe(TimeSpan.FromSeconds(18));
+        result.EffectiveCallTimeout.ShouldBe(TimeSpan.FromSeconds(45));
+        result.ProbeTimeoutSeconds.ShouldBe(30);
+    }
 }

tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/OpcUaClientDriverPageFormSerializationTests.cs

@@ -1,7 +1,9 @@
+using System.Collections.Generic;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 using Shouldly;
 using Xunit;
+using ZB.MOM.WW.OtOpcUa.AdminUI.Components.Pages.Clusters.Drivers;
 using ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient;
 
 namespace ZB.MOM.WW.OtOpcUa.AdminUI.Tests;
@@ -79,4 +81,76 @@ public sealed class OpcUaClientDriverPageFormSerializationTests
         back.ShouldNotBeNull();
         back.ProbeTimeoutSeconds.ShouldBe(20);
     }
+
+    [Fact]
+    public void FormModel_RoundTrip_PreservesAllFields()
+    {
+        // Construct options with non-default values for every editable property plus
+        // non-empty EndpointUrls and UnsMappingTable — both are "read-only" in the form
+        // but must survive the FormModel translation unchanged.
+        var endpointUrls = new List<string> { "opc.tcp://primary:4840", "opc.tcp://backup:4840" };
+        var unsMappingTable = new Dictionary<string, string>
+        {
+            ["Line1/"] = "Site/Area1/Line1",
+            ["Line2/"] = "Site/Area1/Line2",
+        };
+
+        var original = new OpcUaClientDriverOptions
+        {
+            EndpointUrl              = "opc.tcp://fallback:4840",
+            EndpointUrls             = endpointUrls,
+            ApplicationUri           = "urn:test:OtOpcUa:GatewayClient",
+            SessionName              = "TestSession",
+            SecurityMode             = OpcUaSecurityMode.SignAndEncrypt,
+            SecurityPolicy           = OpcUaSecurityPolicy.Basic256Sha256,
+            AuthType                 = OpcUaAuthType.Username,
+            Username                 = "opcuser",
+            Password                 = "p@ssw0rd",
+            UserCertificatePath      = @"C:\certs\user.pfx",
+            UserCertificatePassword  = "certpass",
+            PerEndpointConnectTimeout = TimeSpan.FromSeconds(4),
+            Timeout                  = TimeSpan.FromSeconds(12),
+            SessionTimeout           = TimeSpan.FromSeconds(150),
+            KeepAliveInterval        = TimeSpan.FromSeconds(7),
+            ReconnectPeriod          = TimeSpan.FromSeconds(8),
+            AutoAcceptCertificates   = true,
+            BrowseRoot               = "i=85",
+            MaxDiscoveredNodes       = 3000,
+            MaxBrowseDepth           = 5,
+            TargetNamespaceKind      = OpcUaTargetNamespaceKind.SystemPlatform,
+            UnsMappingTable          = unsMappingTable,
+            ProbeTimeoutSeconds      = 25,
+        };
+
+        var form = OpcUaClientDriverPage.OpcUaClientFormModel.FromRecord(original);
+        var result = form.ToRecord();
+
+        result.EndpointUrl.ShouldBe("opc.tcp://fallback:4840");
+        result.EndpointUrls.Count.ShouldBe(2);
+        result.EndpointUrls[0].ShouldBe("opc.tcp://primary:4840");
+        result.EndpointUrls[1].ShouldBe("opc.tcp://backup:4840");
+        result.ApplicationUri.ShouldBe("urn:test:OtOpcUa:GatewayClient");
+        result.SessionName.ShouldBe("TestSession");
+        result.SecurityMode.ShouldBe(OpcUaSecurityMode.SignAndEncrypt);
+        result.SecurityPolicy.ShouldBe(OpcUaSecurityPolicy.Basic256Sha256);
+        result.AuthType.ShouldBe(OpcUaAuthType.Username);
+        result.Username.ShouldBe("opcuser");
+        result.Password.ShouldBe("p@ssw0rd");
+        result.UserCertificatePath.ShouldBe(@"C:\certs\user.pfx");
+        result.UserCertificatePassword.ShouldBe("certpass");
+        result.PerEndpointConnectTimeout.ShouldBe(TimeSpan.FromSeconds(4));
+        result.Timeout.ShouldBe(TimeSpan.FromSeconds(12));
+        result.SessionTimeout.ShouldBe(TimeSpan.FromSeconds(150));
+        result.KeepAliveInterval.ShouldBe(TimeSpan.FromSeconds(7));
+        result.ReconnectPeriod.ShouldBe(TimeSpan.FromSeconds(8));
+        result.AutoAcceptCertificates.ShouldBeTrue();
+        result.BrowseRoot.ShouldBe("i=85");
+        result.MaxDiscoveredNodes.ShouldBe(3000);
+        result.MaxBrowseDepth.ShouldBe(5);
+        result.TargetNamespaceKind.ShouldBe(OpcUaTargetNamespaceKind.SystemPlatform);
+        result.UnsMappingTable.Count.ShouldBe(2);
+        result.UnsMappingTable["Line1/"].ShouldBe("Site/Area1/Line1");
+        result.UnsMappingTable["Line2/"].ShouldBe("Site/Area1/Line2");
+        result.ProbeTimeoutSeconds.ShouldBe(25);
+    }
 }

tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/S7DriverPageFormSerializationTests.cs

@@ -69,6 +69,12 @@ public sealed class S7DriverPageFormSerializationTests
     [Fact]
     public void FormModel_RoundTrip_PreservesEditableFields()
     {
+        var tags = new[]
+        {
+            new S7TagDefinition("Speed",  "DB1.DBD0",  S7DataType.Float32, Writable: true),
+            new S7TagDefinition("Status", "DB1.DBW4",  S7DataType.Int16,   Writable: false),
+        };
+
         var opts = new S7DriverOptions
         {
             Host = "192.168.1.50",
@@ -84,6 +90,7 @@ public sealed class S7DriverPageFormSerializationTests
                 Timeout = TimeSpan.FromSeconds(4),
             },
             ProbeTimeoutSeconds = 20,
+            Tags = tags,
         };
 
         var form = ZB.MOM.WW.OtOpcUa.AdminUI.Components.Pages.Clusters.Drivers
@@ -100,5 +107,14 @@ public sealed class S7DriverPageFormSerializationTests
         roundTripped.Probe.Interval.ShouldBe(TimeSpan.FromSeconds(8));
         roundTripped.Probe.Timeout.ShouldBe(TimeSpan.FromSeconds(4));
         roundTripped.ProbeTimeoutSeconds.ShouldBe(20);
+
+        // Tags must survive the FormModel round-trip unchanged (regression guard for the
+        // Tags = [] data-loss bug fixed in this PR).
+        roundTripped.Tags.Count.ShouldBe(2);
+        roundTripped.Tags[0].Name.ShouldBe("Speed");
+        roundTripped.Tags[0].Address.ShouldBe("DB1.DBD0");
+        roundTripped.Tags[0].DataType.ShouldBe(S7DataType.Float32);
+        roundTripped.Tags[1].Name.ShouldBe("Status");
+        roundTripped.Tags[1].Writable.ShouldBeFalse();
     }
 }