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/app/dashboard/conversations/_components/chat-panel.tsx

@@ -350,7 +350,7 @@ export function ChatPanel() {
   const messagesScroll = (
     <div
       ref={messagesContainerRef}
-      className="h-full min-h-0 flex-1 overflow-y-auto p-4 cs-agent-scrollbar"
+      className="h-full min-h-0 flex-1 overflow-y-auto p-4 cs-ai-agent-scrollbar"
     >
       <div ref={messagesContentRef} className="flex flex-col">
         {!loading && messages.length > 0 && messagesHasMore ? (