Notes on verification

Core facts (date, patron, location, reconciliation context) are corroborated by Wikipedia, an academic paper, and Yale's library catalog. However, Charles was Lothar's half-brother, not full brother, and some recent scholarship dates production to c. 842 rather than strictly tying it to the 849 reconciliation, so the traditional framing is not universally accepted. [cascade flags: wikipedia_dropped_other_sources_exist | tier=silver indep_score=0.875 clusters=2 claim_tier=notable]