refactor: rename agent widget references to AI agent for consistency

- Updated runtime configuration to use __CS_AI_AGENT_WIDGET_CONFIG__ instead of __CS_AGENT_WIDGET_CONFIG__.
- Changed message types in support host bridge from "cs-agent" to "cs-ai-agent".
- Minified SDK script updated to reflect new AI agent naming conventions.
- Adjusted scrollbar styles in main.scss to use .cs-ai-agent-scrollbar instead of .cs-agent-scrollbar.

web/components/support-chat/message-list.tsx

@@ -219,7 +219,7 @@ export const SupportChatMessageList = forwardRef<SupportChatMessageListHandle, S
     return (
       <div
         ref={containerRef}
-        className="cs-agent-scrollbar flex min-h-0 flex-1 flex-col gap-4 overflow-y-auto px-4 py-4"
+        className="cs-ai-agent-scrollbar flex min-h-0 flex-1 flex-col gap-4 overflow-y-auto px-4 py-4"
       >
         <div ref={contentRef} className="flex flex-col gap-4">
           {hasMoreOlder && onLoadOlder ? (