What is the ruling on one of the contracting parties unilaterally rescinding a binding contract, especially in a manufacturing (Istisna') contract, and does the ruling differ based on the type of contract?

Necessary contracts cannot be unilaterally revoked by either party without a valid excuse. If one party revokes the contract without a valid excuse, the contract does not become void, and its effects remain. The contracting party is entitled to compensation. This applies to leasing (ijarah) and manufacturing contracts (istisna'). Therefore, if someone leases a property or commissions the manufacturing of something, and then retracts without a valid excuse, they are obligated to pay the full rent or price. The manufacturer is obliged to deliver the commissioned item, and the commissioner is obliged to pay the agreed price.