fix: hide zap reply previews for missing or non-chat events

Only show reply previews for zaps when:
1. The replied-to event exists in the event store
2. The replied-to event is a chat kind (9, 9321, or 1311)

This prevents showing loading states or reply previews for
zaps replying to events we don't have or non-chat events.

src/components/ChatViewer.tsx

@@ -269,6 +269,19 @@ const MessageItem = memo(function MessageItem({
       zapRequest?.tags.find((t) => t[0] === "e")?.[1] ||
       undefined;
 
+    // Check if the replied-to event exists and is a chat kind
+    const replyEvent = use$(
+      () => (zapReplyTo ? eventStore.event(zapReplyTo) : undefined),
+      [zapReplyTo],
+    );
+
+    // Only show reply preview if:
+    // 1. The event exists in our store
+    // 2. The event is a chat kind (9, 9321, 1311)
+    const chatKinds = [9, 9321, 1311];
+    const shouldShowReplyPreview =
+      zapReplyTo && replyEvent && chatKinds.includes(replyEvent.kind);
+
     return (
       <div className="pl-2 my-1">
         <div
@@ -300,7 +313,7 @@ const MessageItem = memo(function MessageItem({
                 <Timestamp timestamp={message.timestamp} />
               </span>
             </div>
-            {zapReplyTo && (
+            {shouldShowReplyPreview && (
               <ReplyPreview
                 replyToId={zapReplyTo}
                 adapter={adapter}