Fix AI homepage title visibility: use isolation:isolate instead of overflow:hidden

Co-authored-by: interstellarmt <178904023+interstellarmt@users.noreply.github.com>
Agent-Logs-Url: https://github.com/antvis/dumi-theme-antv/sessions/85352e60-2f51-4620-af4d-4471dc9228da

Author: Copilot

src/components/AI/HomeDialog/index.module.less

@@ -1,9 +1,8 @@
 .content {
   height: 500px;
-  overflow: hidden;
+  isolation: isolate;
 
   @media only screen and (max-width: 767.99px) {
     height: auto;
-    overflow: visible;
   }
 }