feat(event): implement PlatformUnaryViewResponder

Sources/OpenSwiftUI/Event/Responder/PlatformUnaryViewResponder.swift

@@ -0,0 +1,48 @@
+//
+//  PlatformUnaryViewResponder.swift
+//  OpenSwiftUI
+//
+//  Audited for 6.5.4
+//  Status: Complete
+
+#if os(iOS) || os(visionOS) || os(macOS)
+@_spi(ForOpenSwiftUIOnly)
+import OpenSwiftUICore
+
+class PlatformUnaryViewResponder: PlatformViewResponder {
+    var layoutResponder: DefaultLayoutViewResponder
+
+    init(layoutResponder: DefaultLayoutViewResponder) {
+        self.layoutResponder = layoutResponder
+        super.init()
+        layoutResponder.parent = self
+    }
+
+    override func bindEvent(_ event: any EventType) -> ResponderNode? {
+        layoutResponder.bindEvent(event)
+    }
+
+    override func makeGesture(inputs: _GestureInputs) -> _GestureOutputs<Void> {
+        layoutResponder.makeGesture(inputs: inputs)
+    }
+
+    override func resetGesture() {
+        layoutResponder.resetGesture()
+    }
+
+    override var children: [ViewResponder] {
+        [layoutResponder]
+    }
+
+    @discardableResult
+    override func visit(
+        applying visitor: (ResponderNode) -> ResponderVisitorResult
+    ) -> ResponderVisitorResult {
+        let result = visitor(self)
+        guard result == .next else {
+            return result
+        }
+        return layoutResponder.visit(applying: visitor)
+    }
+}
+#endif