refactor(chat): migrate simple bubble styles to tailwind

src/app/chat/components/message-avatar.tsx

@@ -2,23 +2,26 @@
 import Image from "next/image";
 
 import { UserMessageAvatar } from "@/app/_components";
-import styles from "./message-avatar.module.css";
 
 export interface MessageAvatarProps {
   isFromAI: boolean;
   userAvatarUrl?: string | null;
 }
 
+const AVATAR_CLASS_NAME =
+  "flex size-[var(--chat-avatar-size,43px)] shrink-0 items-center justify-center overflow-hidden rounded-full border-2 border-[var(--color-avatar-border,#fbf3f5)] bg-[var(--color-avatar-border,#fbf3f5)] shadow-[var(--shadow-input-box,0_1px_2px_rgba(0,0,0,0.1))]";
+
 export function MessageAvatar({ isFromAI, userAvatarUrl }: MessageAvatarProps) {
   if (isFromAI) {
     return (
-      <div className={styles.avatar} aria-label="AI avatar">
+      <div className={AVATAR_CLASS_NAME} aria-label="AI avatar">
         <Image
           src="/images/chat/pic-chat-elio.png"
           alt="Elio"
           width={43}
           height={43}
           priority
+          className="size-full object-cover"
         />
       </div>
     );