In their pitch for a merger of the UConn Health Center and Hartford Hospital, University of Connecticut officials said their plan could represent a détente in the area's long-running hospital wars. But leaders of St. Francis Hospital and Medical Center in Hartford and Bristol Hospital say the proposal, which includes the state-funded construction of a $475 million hospital, amounts to state taxpayers' giving two of their competitors a new hospital and a major edge at a time when other hospitals are struggling to balance the books.