Correlate primary and fallback attempts before diagnosing displayed caller identity

A successful fallback call does not establish what happened on the primary attempt. In any retry chain that can change routing identity, correlate operations before diagnosing a caller-ID rewrite: a terminal primary operation followed by an answered fallback explains the fallback identity, while one answered primary operation with the intended identity present points to a downstream rewrite.

Applicability and limits: use provider operation IDs, attempt lineage, authenticated signaling traces, and a fresh configuration read. Preserve the intended primary identity and any bounded emergency fallback while testing the smallest change. A displayed number alone cannot identify which path connected, and a missing header is only a hypothesis until it is tied to the exact call and active configuration.