feat: add creative welcome and external works square links

src/components/layout/Sidebar.tsx

@@ -53,6 +53,7 @@ import { useProviderStore } from '@/stores/providers';
 import type { CodingProjectSummary } from '@/types/coding-project';
 import { useProjectConfigStore } from '@/stores/project-config';
 import { toast } from 'sonner';
+import { CommunityLink } from '@/components/community/CommunityLink';
 
 type OpenDialogResult = {
   canceled: boolean;
@@ -435,6 +436,7 @@ export function Sidebar({
           <Plus className="h-4 w-4 shrink-0 text-brand" />
           {!sidebarCollapsed && '新建项目'}
         </button>
+        <CommunityLink variant="sidebar" collapsed={sidebarCollapsed} />
         <div className="classroom-projects mt-3">
           <button
             type="button"