Use Task.Run with capture for Action<T> APM calls

Opt-in port of ignored bound Action<T>.BeginInvoke(value,null,null) statements for simple reference/enum/primitive and attested BCL value argument types. A typed private void helper captures receiver/value in order, preserves immediate input/null failures, then schedules Invoke with Task.Run. Include statement-bodied lambdas/anonymous delegates, which cannot be C# expression trees; leave expression-bodied lambdas/queries and generic/partial owners unchanged. Adopt Task scheduling, child-task/unobserved-exception behavior and helper/closure frames. Leave other delegate shapes/callbacks/state/observed/named calls and existing companion boundaries unchanged. Separate from version upgrades.