feat: 工作台左侧导航新增「知识库」入口

之前只加在了 strategy shell 的 sidebar-menu，工作台 shell 用的是 WorkspaceNavChatList，这里补上入口指向 /page/workspace/knowledge。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend-web/src/components/workspace/workspace-nav-chat-list.tsx

@@ -14,7 +14,7 @@ import {
 } from "@/components/ui/sidebar";
 import { useI18n } from "@/core/i18n/hooks";
 // import { BotIcon, BrainIcon, ListChecks, MessageSquarePlus, MessagesSquare, SparklesIcon, UsersIcon } from "lucide-react";
-import { BotIcon, BrainIcon, ListChecks, MessageSquarePlus, MessagesSquare, PenLine, SparklesIcon, Users } from "lucide-react";
+import { BookOpen, BotIcon, BrainIcon, ListChecks, MessageSquarePlus, MessagesSquare, PenLine, SparklesIcon, Users } from "lucide-react";
 
 import { SidebarCollapseButton } from "./workspace-header";
 import { WorkspaceNavStudio } from "./workspace-nav-studio";
@@ -164,6 +164,18 @@ export function WorkspaceNavChatList({
                 </Link>
               </SidebarMenuButton>
             </SidebarMenuItem>
+            <SidebarMenuItem>
+              <SidebarMenuButton
+                isActive={pathname.startsWith("/page/workspace/knowledge")}
+                asChild
+                className={NAV_ITEM_CLASS}
+              >
+                <Link href="/page/workspace/knowledge">
+                  <BookOpen />
+                  <span>知识库</span>
+                </Link>
+              </SidebarMenuButton>
+            </SidebarMenuItem>
           </>
         )}
       </SidebarMenu>