Replace emoji avatars with image avatars for chat participants

- Update addMessage() function to use image elements instead of emojis
- Update createStreamingMessageContainer() function for assistant avatar
- Replace default assistant message emoji with image in index.html
- Assistant avatar: https://files.catbox.moe/cbclyf.png
- User avatar: https://files.catbox.moe/m5qftn.png

index.html

@@ -273,7 +273,9 @@
 
         <div class="chat-container" id="chatContainer">
             <div class="message assistant">
-                <div class="message-avatar">🎤</div>
+                <div class="message-avatar">
+                    <img src="https://files.catbox.moe/cbclyf.png" alt="Assistant" style="width: 100%; height: 100%; border-radius: 50%; object-fit: cover;">
+                </div>
                 <div class="message-content">
                     Hello! I'm Hatsune Miku, your virtual assistant. How can I help you today?
                 </div>

index.js

@@ -134,7 +134,17 @@ function addMessage(role, content) {
     
     const avatar = document.createElement('div');
     avatar.className = 'message-avatar';
-    avatar.textContent = role === 'user' ? '👤' : '🤖';
+    
+    // Create image element for avatar
+    const avatarImg = document.createElement('img');
+    avatarImg.src = role === 'user' ? 'https://files.catbox.moe/m5qftn.png' : 'https://files.catbox.moe/cbclyf.png';
+    avatarImg.alt = role === 'user' ? 'User' : 'Assistant';
+    avatarImg.style.width = '100%';
+    avatarImg.style.height = '100%';
+    avatarImg.style.borderRadius = '50%';
+    avatarImg.style.objectFit = 'cover';
+    
+    avatar.appendChild(avatarImg);
     
     const contentDiv = document.createElement('div');
     contentDiv.className = 'message-content';
@@ -156,7 +166,17 @@ function createStreamingMessageContainer() {
     
     const avatar = document.createElement('div');
     avatar.className = 'message-avatar';
-    avatar.textContent = '🤖';
+    
+    // Create image element for avatar
+    const avatarImg = document.createElement('img');
+    avatarImg.src = 'https://files.catbox.moe/cbclyf.png';
+    avatarImg.alt = 'Assistant';
+    avatarImg.style.width = '100%';
+    avatarImg.style.height = '100%';
+    avatarImg.style.borderRadius = '50%';
+    avatarImg.style.objectFit = 'cover';
+    
+    avatar.appendChild(avatarImg);
     
     const contentDiv = document.createElement('div');
     contentDiv.className = 'message-content';