fix(apple): disarm CHHapticEngine handlers with no-ops, not nil

stoppedHandler/resetHandler are non-optional closures on the CI SDK
((StoppedReason)->() and ()->()), so assigning nil fails to compile
(apple.yml). Assign no-op closures to disarm them before engine.stop()
-- same re-entrancy guard intent, type-correct.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/apple/Sources/PunktfunkKit/GamepadFeedback.swift

@@ -186,9 +186,10 @@ private final class RumbleRenderer: @unchecked Sendable {
 
     private func teardown() {
         for m in [low, high].compactMap({ $0 }) {
-            // Drop the handlers before stopping so stop() can't re-enter teardown via stoppedHandler.
-            m.engine.stoppedHandler = nil
-            m.engine.resetHandler = nil
+            // Disarm the handlers before stopping so stop() can't re-enter teardown via them.
+            // (Both properties are non-optional closures on this SDK, so assign no-ops, not nil.)
+            m.engine.stoppedHandler = { _ in }
+            m.engine.resetHandler = {}
             try? m.player.stop(atTime: CHHapticTimeImmediate)
             m.engine.stop()
         }