perf(site-runtime): ScriptActor trigger expressions evaluate on the script scheduler, coalesced, edge state actor-confined (P1)

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

@@ -303,6 +303,43 @@ public class ScriptActorTests : TestKit, IDisposable
     private Script<object?> CompileTriggerExpression(string expression) =>
         _compilationService.CompileTriggerExpression("trigger-expr", expression).CompiledScript!;
 
+    /// <summary>
+    /// Compiles a trigger expression WITHOUT the trust validator so a test can use
+    /// <c>System.Threading.Thread</c> (forbidden in real scripts) to observe which
+    /// thread the evaluation runs on. Mirrors the real compile against
+    /// <see cref="TriggerExpressionGlobals"/>.
+    /// </summary>
+    private static Script<object?> CompileRawTriggerExpression(string expression)
+    {
+        var opts = ScriptOptions.Default
+            .WithReferences(typeof(object).Assembly, typeof(Enumerable).Assembly)
+            .WithImports("System", "System.Collections.Generic", "System.Linq", "System.Threading.Tasks");
+        var s = CSharpScript.Create<object?>(expression, opts, typeof(TriggerExpressionGlobals));
+        s.Compile();
+        return s;
+    }
+
+    [Fact]
+    public void ExpressionTrigger_EvaluatesOnScriptSchedulerThread_AndStillFires()
+    {
+        // The expression is TRUE only when evaluated on a script-execution thread.
+        // Before P1 it ran synchronously on the actor's dispatcher thread (name is
+        // NOT "script-execution-*") → false → no fire. After P1 it runs on the
+        // script scheduler → true → fire.
+        var expr = CompileRawTriggerExpression(
+            "System.Threading.Thread.CurrentThread.Name != null && " +
+            "System.Threading.Thread.CurrentThread.Name.StartsWith(\"script-execution-\")");
+        var (actor, instance) = CreateTriggeredActor(
+            "ExprThread",
+            "Expression",
+            "{\"expression\":\"true\",\"mode\":\"OnTrue\"}",
+            minTimeBetweenRuns: null,
+            expr);
+
+        actor.Tell(Change("Any", "1"));
+        instance.ExpectMsg<SetStaticAttributeCommand>(TimeSpan.FromSeconds(10)); // fired ⇒ evaluated off-dispatcher
+    }
+
     [Fact]
     public void ScriptActor_ConditionalWhileTrue_FiresOnEdgeThenReFiresWhileConditionHolds()
     {