feat(adminui): typed native-alarm section in the raw tag modal (#642)

NativeAlarmModel: IsAlarm=false now removes the alarm key; advisory Warnings, driver gating, order-safe Edit.

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Uns/TagEditors/NativeAlarmModel.cs

@@ -90,14 +90,72 @@ public sealed class NativeAlarmModel
             // Re-attach (no-op when it was already the same node; required when we created a fresh one).
             _root["alarm"] = alarm;
         }
+        else
+        {
+            // Toggled off (#642): the alarm object must go, or a "disabled" tag would still deploy as a condition.
+            _root.Remove("alarm");
+        }
 
         return TagConfigJson.Serialize(_root);
     }
 
     /// <summary>Validation hook; returns an error message or null when the model is valid.</summary>
     /// <returns>An error message describing the validation failure, or null when the model is valid.</returns>
+    /// <remarks>Deliberately never errors: the deploy gate has no <c>alarm</c> rule and
+    /// <c>TagConfigIntent.ParseAlarm</c> accepts any alarmType string and any severity (clamped 1..1000 at
+    /// publish), so rejecting here would be stricter than the gate. Out-of-range input is advisory —
+    /// see <see cref="Warnings"/>.</remarks>
     public string? Validate() => null;
 
+    /// <summary>Advisory messages for values the server will accept but silently normalise.</summary>
+    /// <returns>Zero or more warning strings.</returns>
+    public IEnumerable<string> Warnings()
+    {
+        if (!IsAlarm) { yield break; }
+        if (Severity is < 1 or > 1000)
+        {
+            yield return $"Severity {Severity} is outside 1..1000; the server clamps it.";
+        }
+        if (!KnownAlarmTypes.Contains(AlarmType))
+        {
+            yield return $"Alarm type '{AlarmType}' is not one of {string.Join("/", KnownAlarmTypes)}; the server treats it as AlarmCondition.";
+        }
+    }
+
+    /// <summary>The Part 9 condition subtypes the server distinguishes (OffNormal/Discrete; the rest map to the base condition).</summary>
+    public static readonly IReadOnlyList<string> KnownAlarmTypes =
+        ["AlarmCondition", "OffNormalAlarm", "DiscreteAlarm", "LimitAlarm"];
+
+    /// <summary>Driver types that implement <c>IAlarmSource</c> (so a TagConfig <c>alarm</c> object is
+    /// meaningful). The alarm object itself is driver-agnostic; this only gates the editor's visibility.</summary>
+    private static readonly HashSet<string> AlarmDriverTypes = new(StringComparer.OrdinalIgnoreCase)
+    {
+        Core.Abstractions.DriverTypeNames.MTConnect, Core.Abstractions.DriverTypeNames.AbCip,
+        Core.Abstractions.DriverTypeNames.FOCAS, Core.Abstractions.DriverTypeNames.OpcUaClient,
+        Core.Abstractions.DriverTypeNames.Galaxy,
+    };
+
+    /// <summary>True when the driver type can emit native alarms.</summary>
+    /// <param name="driverType">Driver type name.</param>
+    /// <returns>Whether the native-alarm editor applies.</returns>
+    public static bool SupportsNativeAlarms(string? driverType)
+        => driverType is not null && AlarmDriverTypes.Contains(driverType);
+
+    /// <summary>
+    /// Order-safe edit: re-parses the LATEST <paramref name="json"/> (so a keystroke in the per-driver
+    /// editor is never overwritten by a stale cached copy), applies <paramref name="mutate"/>, serialises.
+    /// Only the <c>alarm</c> key is touched; every other key is preserved verbatim.
+    /// </summary>
+    /// <param name="json">Current TagConfig JSON.</param>
+    /// <param name="mutate">Edit to apply to the freshly-parsed model.</param>
+    /// <returns>The new TagConfig JSON.</returns>
+    public static string Edit(string? json, Action<NativeAlarmModel> mutate)
+    {
+        var m = FromJson(json);
+        mutate(m);
+        return m.ToJson();
+    }
+
     /// <summary>Default <c>alarmType</c> seeded when an alarm-bearing attribute is picked but the
     /// TagConfig has no <c>alarm</c> object yet. Galaxy's <c>AlarmExtension</c> is a boolean
     /// off-normal condition, so <c>OffNormalAlarm</c> is the natural Part 9 subtype.</summary>