feat: add player camera

src/components/ui/Crosshair.tsx

@@ -0,0 +1,11 @@
+import { useCameraMode } from "@/debug/useCameraMode";
+
+export function Crosshair(): React.JSX.Element | null {
+  const cameraMode = useCameraMode();
+
+  if (cameraMode !== "player") {
+    return null;
+  }
+
+  return <div className="crosshair" aria-hidden="true" />;
+}