Why Does Passing NSManagedObjectContext Across Isolation Domains No Longer Error in Swift 6.2? The Real Change Isn't in the Compiler

This post documents a recent debugging journey: starting from a test failure, tracing all the way down to the Core Data SDK interface, and ultimately discovering that the key change had nothing to do with the Swift compiler itself — it was how NSManagedObjectContext is imported into Swift that had changed.