feat(triggers): add Expression to the script & alarm trigger codecs

src/ScadaLink.CentralUI/Components/Shared/ScriptTriggerConfigCodec.cs

@@ -10,7 +10,7 @@ namespace ScadaLink.CentralUI.Components.Shared;
 /// trigger; <see cref="Unknown"/> is a stored trigger-type string the runtime
 /// does not recognize (preserved as-is by the editor).
 /// </summary>
-internal enum ScriptTriggerKind { None, Interval, ValueChange, Conditional, Call, Unknown }
+internal enum ScriptTriggerKind { None, Interval, ValueChange, Conditional, Call, Expression, Unknown }
 
 /// <summary>A script's trigger as the editor emits it: a type string + config JSON.</summary>
 public sealed record ScriptTriggerValue(string? TriggerType, string? Config);
@@ -29,6 +29,9 @@ internal sealed class ScriptTriggerModel
 
     /// <summary>Comparison threshold (Conditional).</summary>
     public double? Threshold { get; set; }
+
+    /// <summary>Boolean C# expression (Expression).</summary>
+    public string? Expression { get; set; }
 }
 
 /// <summary>
@@ -59,6 +62,7 @@ internal static class ScriptTriggerConfigCodec
             "valuechange" => ScriptTriggerKind.ValueChange,
             "conditional" => ScriptTriggerKind.Conditional,
             "call" => ScriptTriggerKind.Call,
+            "expression" => ScriptTriggerKind.Expression,
             _ => ScriptTriggerKind.Unknown
         };
     }
@@ -70,6 +74,7 @@ internal static class ScriptTriggerConfigCodec
         ScriptTriggerKind.ValueChange => "ValueChange",
         ScriptTriggerKind.Conditional => "Conditional",
         ScriptTriggerKind.Call => "Call",
+        ScriptTriggerKind.Expression => "Expression",
         _ => null
     };
 
@@ -104,6 +109,10 @@ internal static class ScriptTriggerConfigCodec
                     model.Operator = NormalizeOperator(op);
                     model.Threshold = TryReadDouble(root, "threshold") ?? TryReadDouble(root, "value");
                     break;
+
+                case ScriptTriggerKind.Expression:
+                    model.Expression = root.TryGetProperty("expression", out var e) ? e.GetString() : null;
+                    break;
             }
         }
         catch (JsonException)
@@ -144,6 +153,10 @@ internal static class ScriptTriggerConfigCodec
                         w.WriteNumber("threshold", model.Threshold.Value);
                     break;
 
+                case ScriptTriggerKind.Expression:
+                    w.WriteString("expression", model.Expression ?? "");
+                    break;
+
                 // Call → empty object.
             }
             w.WriteEndObject();