Build an emoji blaster animation on iOS

Build an iOS "blaster" app with a button at the bottom; when the user presses and holds, it emits emoji projectiles that animate toward the top of the screen at regular intervals. Specify your animation approach (Core Animation, UIKit Dynamics, or SwiftUI), scheduling/timers for continuous firing, collision or off-screen cleanup, performance considerations for many concurrent animations, and how you would structure the code for testability.