feat(siteruntime): M2.12 (#25) — emit script Error site event on recursion-limit violation

Inject ISiteEventLogger into ScriptRuntimeContext (additive optional ctor
param, defaulted null, all existing callers source-compatible). Add a single
private EmitRecursionLimitEventAsync helper that fires-and-forgets a
"script"/Error site event; called at both recursion guard sites (CallScript
at ~:332 and ScriptCallHelper.CallShared at ~:499). ScriptExecutionActor
threads the already-resolved siteEventLogger singleton into the context;
AlarmExecutionActor leaves it null (no siteEventLogger wired there).

Existing _logger.LogError + throw behaviour unchanged.

Tests: RecursionLimitSiteEventTests — 5 tests covering both CallScript and
CallShared (ISiteEventLogger.LogEventAsync called once with category "script",
severity "Error"; null logger path does not throw).

src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/ScriptExecutionActor.cs

@@ -217,7 +217,11 @@ public class ScriptExecutionActor : ReceiveActor
                     // and the four cached-call telemetry constructors can stamp
                     // it onto NotificationSubmit.SourceNode and
                     // SiteCallOperational.SourceNode respectively.
-                    sourceNode: sourceNode);
+                    sourceNode: sourceNode,
+                    // M2.12 (#25): thread the singleton site event logger so
+                    // recursion-limit violations at CallScript/CallShared emit a
+                    // script Error site event in addition to ILogger.LogError.
+                    siteEventLogger: siteEventLogger);
 
                 var globals = new ScriptGlobals
                 {