Add app icon asset, screenshot exporter, and misc updates

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Shared/Random.swift

@@ -136,8 +136,11 @@ extension View {
     }
 
     func asImage(size: CGSize) -> UIImage {
-        let controller = UIHostingController(rootView: self)
+        let wrapped = self.ignoresSafeArea().frame(width: size.width, height: size.height)
+        let controller = UIHostingController(rootView: wrapped)
         controller.view.bounds = CGRect(origin: .zero, size: size)
+        controller.view.backgroundColor = .clear
+        controller.view.layoutIfNeeded()
         let image = controller.view.asImage()
         return image
     }