merge: 合并 origin/xuhd，解决 message-list-item 和 WorkspaceRoutes 冲突

- message-list-item: 保留 EmbeddedPageContext + 消息内联编辑两套功能
- WorkspaceRoutes: 保留 IframeChatPage + NotebookDetailPageWithKey

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend-web/src/components/workspace/chats/chat-box.tsx

@@ -384,14 +384,14 @@ const ChatBox: React.FC<{
       />
       <ResizablePanel
         className={cn(
-          "bg-[#fffdfa] transition-all duration-300 ease-in-out",
+          "bg-background transition-all duration-300 ease-in-out",
           !sidePanelOpen && "opacity-0",
         )}
         id="artifacts"
       >
         <div
           className={cn(
-            "h-full bg-[#fffdfa] p-4 transition-transform duration-300 ease-in-out",
+            "h-full bg-background p-4 transition-transform duration-300 ease-in-out",
             sidePanelOpen ? "translate-x-0" : "translate-x-full",
           )}
         >