fix: 修复微信悬浮球图标为群聊图标，保持二维码原始比例

Author: CC11001100

src/components/WechatFloat.css

@@ -37,8 +37,8 @@
 }
 
 .wechat-popup img {
-  width: 180px;
-  height: 180px;
+  max-width: 220px;
+  height: auto;
   border-radius: 8px;
 }
 

src/components/WechatFloat.tsx

@@ -10,7 +10,11 @@ export default function WechatFloat() {
       onMouseEnter={() => setIsHovered(true)}
       onMouseLeave={() => setIsHovered(false)}
     >
-      <div className="wechat-icon">💬</div>
+      <div className="wechat-icon">
+        <svg viewBox="0 0 24 24" width="28" height="28" fill="white">
+          <path d="M8.5 11.5a1 1 0 1 1 0-2 1 1 0 0 1 0 2zm4 0a1 1 0 1 1 0-2 1 1 0 0 1 0 2zm-6.5 5a1 1 0 1 1 0-2 1 1 0 0 1 0 2zm4 0a1 1 0 1 1 0-2 1 1 0 0 1 0 2zM9 3C4.58 3 1 6.13 1 10c0 2.17 1.16 4.1 3 5.38V19l3.5-2.1c.5.07 1 .1 1.5.1 4.42 0 8-3.13 8-7s-3.58-7-8-7zm6.5 16.5l2.5 1.5v-2.62c1.84-1.28 3-3.21 3-5.38 0-2.17-1.16-4.1-3-5.38V5c2.76 1.5 4.5 4.5 4.5 8 0 5-4.03 9-9 9-.5 0-1-.03-1.5-.1l3-1.9z"/>
+        </svg>
+      </div>
       {isHovered && (
         <div className="wechat-popup">
           <img src="./wechat-qr.png" alt="微信二维码" />