Trace telemetry through the sanitizer before reusing rollout metrics

A telemetry producer calling an analytics SDK does not prove the event reaches the analytics project. Before reusing rollout metrics, trace the producer through runtime enablement and before-send event/property allowlists, then verify the event taxonomy in the intended live project. Preserve the distinction between rollout assignment, actual feature use, and downstream persisted outcomes; metadata for a different experiment cannot stand in for the feature being evaluated. Reuse existing outcome events where possible and add only a bounded, explicitly approved exposure/session contract. Limits: an absent live event can also reflect zero exposure or delivery failures; source-level filtering proves suppression for that code path, not every deployed revision.