fix(site-runtime): resolve SiteRuntime-017..019 — isolated attribute snapshot for child actors, corrected dispatcher doc, remove dead lifecycle handlers

src/ScadaLink.SiteRuntime/Actors/ScriptExecutionActor.cs

@@ -14,9 +14,14 @@ namespace ScadaLink.SiteRuntime.Actors;
 /// <summary>
 /// WP-15: Script Execution Actor -- short-lived child of Script Actor.
 /// Receives compiled code, params, Instance Actor ref, and call depth.
-/// Runs on a dedicated blocking I/O dispatcher.
 /// Executes the script via Script Runtime API, returns result, then stops.
 ///
+/// The actor itself and its mailbox run on the default Akka dispatcher; only the
+/// script body is dispatched off the actor thread, onto the dedicated
+/// <see cref="ScadaLink.SiteRuntime.Scripts.ScriptExecutionScheduler"/>
+/// (SiteRuntime-009), so blocking script I/O cannot starve the shared thread pool
+/// or stall other Akka dispatchers.
+///
 /// WP-32: Script failures are logged but do not disable the script.
 /// Supervision: Stop on unhandled exception (parent ScriptActor decides).
 /// </summary>