fix: add parens around nullish coalescing in PostDetailDialog (build error)

src/components/feed/PostDetailDialog.tsx

@@ -121,7 +121,7 @@ export function PostDetailDialog({ post, open, onClose, onDeleted }: PostDetailD
         setTimeout(() => commentsEndRef.current?.scrollIntoView({ behavior: "smooth" }), 150);
       },
       onError: () => {
-        setBody((prev) => prev || pendingBody ?? "");
+        setBody((prev) => prev || (pendingBody ?? ""));
         setPendingBody(null);
         toast.error(tc("postError"));
       },