feat(frontend): 不带 sidebar 的聊天页顶栏右侧也展示名称+岗位

紧凑布局（无全局 Header）下复用 UserIdentityBadge，数据源与全量模式 Header 一致，仅在 !compactChrome 时渲染，避免与全局顶栏重复。

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

frontend-web/src/pages/ChatPage.tsx

@@ -27,6 +27,7 @@ import { QuestionNavigator } from "@/components/workspace/question-navigator";
 import { ThreadTitle } from "@/components/workspace/thread-title";
 import { TodoList } from "@/components/workspace/todo-list";
 import { TokenUsageIndicator } from "@/components/workspace/token-usage-indicator";
+import { UserIdentityBadge } from "@/components/workspace/user-identity-badge";
 import { Welcome } from "@/components/workspace/welcome";
 import { CompactWelcome } from "@/components/workspace/compact-welcome";
 import { readSidebarEnabled } from "@/core/page-layout/sidebar-enabled";
@@ -481,6 +482,17 @@ export default function ChatPage() {
               <ExportTrigger threadId={threadId} />
               <KnowledgeSaveTrigger threadId={threadId} />
               <ArtifactTrigger />
+              {/* 不带全局顶栏（紧凑模式）时，名称+岗位回落到聊天页顶栏右侧，
+                  与全量模式 Header 右上角保持一致。全量模式已有顶栏则不重复展示。 */}
+              {!compactChrome && (
+                <>
+                  <div
+                    className="bg-border/70 mx-1 h-6 w-px shrink-0"
+                    aria-hidden
+                  />
+                  <UserIdentityBadge />
+                </>
+              )}
             </div>
           </header>
           <main className="flex min-h-0 max-w-full grow flex-col">