Concrete ITagUpstreamSource the scripted-alarm host actor pushes
DependencyValueChanged values into and ScriptedAlarmEngine reads/subscribes
from. Thread-safe: ConcurrentDictionary value cache + per-path ImmutableList
observer lists with atomic add/remove and capture-then-invoke fan-out.
ReadTag of an unknown path returns a Bad-quality (0x80000000) snapshot stamped
via the injected clock. Adds the Core.ScriptedAlarms project reference Runtime
needs to see the interface.
Joseph Doherty
945ccd0b85