How Renewals and Restores Affect Transaction IDs in StoreKit 2

StoreKit 2 generates a new transaction ID for every purchase event, including renewals and restores, which can break naive backend logic. The original transaction ID, however, remains constant and should be used to track subscriptions and entitlements. By correctly distinguishing between these identifiers and listening to transaction updates, developers can build reliable in-app purchase systems that persist across devices and lifecycle events.