The UI script editor has no ExecutionTimeoutSeconds control (authoring deferred),
so a body edit silently cleared a timeout set via Transport import. Round-trip the
loaded value so UI edits preserve it. Add the missing AlarmExecutionActor null/<=0
fallback tests for symmetry with ScriptExecutionActor.
Spec promised a per-script timeout but only the global ScriptExecutionTimeoutSeconds
existed. Add nullable TemplateScript.ExecutionTimeoutSeconds threaded through EF +
flattening (ResolvedScript) to ScriptExecutionActor/AlarmExecutionActor, which use
perScript ?? global for the execution CTS. Includes the EF migration for the new column.
ScriptExecutionActor previously emitted only an Error 'script' event on failure.
It now also fire-and-forgets an Info 'script' event when execution starts (right
before RunAsync) and when it completes successfully — giving the operational log
the full started/completed/failed lifecycle. Uses the already-resolved
siteEventLogger; fire-and-forget so the event log can never block or fault the
script's own run.
Extends the SingleServiceProvider test helper to also serve IServiceScopeFactory
(returning a self-scope) so ScriptExecutionActor's serviceProvider.CreateScope()
reaches the logging hot path in tests instead of throwing into the catch.