use `message.id` as React `key`

pages/chat/@id/+Page.tsx

@@ -208,8 +208,7 @@ function Messages({
     <Stack gap="md" justify="flex-start">
       {messages.map((message, index) => (
         <Group
-          // biome-ignore lint/suspicious/noArrayIndexKey: <explanation>
+          key={"id" in message ? message.id : index}
-          key={index}
           justify={message.role === "user" ? "flex-end" : "flex-start"}
         >
           <HoverCard