refactor(chat): reuse fullscreen back button

src/app/chat/components/fullscreen-image-viewer.tsx

@@ -12,6 +12,8 @@
 import { ChevronLeft } from "lucide-react";
 import { useEffect } from "react";
 
+import { BackButton } from "@/app/_components";
+
 import { ChatMediaImage } from "./chat-media-image";
 import styles from "./fullscreen-image-viewer.module.css";
 
@@ -90,14 +92,13 @@ export function FullscreenImageViewer({
       aria-modal="true"
       aria-label="Fullscreen image"
     >
-      <button
-        type="button"
+      <BackButton
         className={styles.backButton}
         onClick={onClose}
-        aria-label="Back"
-      >
-        <ChevronLeft size={34} strokeWidth={2.5} aria-hidden="true" />
-      </button>
+        ariaLabel="Back"
+        iconSize={34}
+        variant="unstyled"
+      />
       <ChatMediaImage
         messageId={messageId}
         remoteUrl={imageUrl}