refactor(frontend): 移除缩放逻辑并调整SDK容器样式

将SDK容器的缩放计算逻辑移除，改为固定不缩放
调整SDK容器的CSS样式，使用绝对定位和vh单位

frontend/styles/main.css

@@ -550,22 +550,22 @@ body {
     left: 0;
     width: 100%;
     height: 100%;
-    display: flex;
-    align-items: center;
-    justify-content: center;
     overflow: hidden;
     z-index: 1;
 }
 
 .digital-human-box .sdk-scaling-wrapper .sdk-inner {
-    transform-origin: center center;
-    width: 100%;
+    position: absolute;
+    top: 0;
+    left: 50%;
     height: 100%;
+    transform: translateX(-50%);
+    transform-origin: center center;
 }
 
 .digital-human-box .sdk-scaling-wrapper .sdk-inner .digital-intelligent-interaction {
-    width: 100% !important;
-    height: 100% !important;
+    width: 177.78vh !important;
+    height: 100vh !important;
 }
 
 /* ===== 覆盖 SDK 字体大小 ===== */