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).