feat: add streaming state to markdown quick actions

- Pass isStreaming prop through message components to disable actions during streaming
- Improve action button styling with icons and better spacing
- Disable buttons while streaming to prevent concurrent actions

app/components/chat/Messages.client.tsx

@@ -100,6 +100,7 @@ export const Messages = forwardRef<HTMLDivElement, MessagesProps>(
                         append={props.append}
                         chatMode={props.chatMode}
                         setChatMode={props.setChatMode}
+                        isStreaming={isStreaming}
                       />
                     )}
                   </div>