Prepares a negotiation by computing the actual Zone of Possible Agreement via a bundled BATNA calculator, and explicitly flags when no ZOPA exists so effort goes into restructuring the deal or walking away instead of grinding on a price gap that can't close. Use whenever the user is preparing for a negotiation (deal terms, salary, vendor contract, partnership), needs to set a walk-away price, or is about to negotiate without having named their BATNA or estimated the counterparty's.
