feat(portal-shell): implement portal-shell with apollo-router integration

M8: portal-shell unified frontend shell (Modular Monolith + micro-kernel).

- Apollo Client -> apollo-router (port 4010, RSC prefetch)

- 5 layouts: classic/focus/split/triple/canvas

- Registry + PluginLoader (dynamic import ssr:false)

- 3-layer props merge, Zustand PluginStore

- 4 widgets: grades/notification-bell/user-menu/class-selector

- config-service: new pluginConfig GraphQL resolver

- apollo-router: CORS + header propagation for portal-shell

- docker-compose.yml: portal-shell service block

apps/portal-shell/src/widgets/topbar/user-menu/index.tsx

@@ -0,0 +1,76 @@
+"use client";
+
+/**
+ * user-menu（topbar / top）
+ *
+ * 通过 useWidgetQuery 查询 apollo-router → iam 子图的 me 数据。
+ * 展示用户头像 + 下拉菜单（昵称 / 邮箱 / 角色）。
+ *
+ * 关联：portal-shell spec §5.6 统一 Hook、M8 验收
+ */
+import { gql } from "@apollo/client";
+import { useState } from "react";
+import { useWidgetQuery } from "@/lib/useWidgetQuery";
+import { useAuth } from "@/providers/AuthProvider";
+import type { PluginProps } from "@/lib/types";
+
+const GET_CURRENT_USER = gql`
+  query GetCurrentUser {
+    me {
+      id
+      name
+      email
+      role
+    }
+  }
+`;
+
+interface MeQueryData {
+  me: { id: string; name: string; email: string; role: string } | null;
+}
+
+export default function UserMenu(_props: PluginProps): React.ReactElement {
+  const { user } = useAuth();
+  const [open, setOpen] = useState(false);
+
+  const { data } = useWidgetQuery<MeQueryData, Record<string, never>>(
+    GET_CURRENT_USER,
+    {},
+  );
+
+  const me = data?.me;
+  const displayName = me?.name ?? user.name;
+  const displayEmail = me?.email ?? user.email;
+  const displayRole = me?.role ?? user.role;
+
+  return (
+    <div className="relative">
+      <button
+        type="button"
+        aria-label="用户菜单"
+        aria-expanded={open}
+        onClick={() => setOpen((v) => !v)}
+        className="flex items-center gap-sm rounded-button bg-surface px-sm py-xs text-ink"
+      >
+        <span
+          aria-hidden
+          className="flex h-heading-3 w-heading-3 items-center justify-center rounded-full bg-accent text-ink-onAccent"
+        >
+          {displayName.charAt(0).toUpperCase()}
+        </span>
+        <span className="text-small">{displayName}</span>
+      </button>
+      {open ? (
+        <ul className="absolute right-0 z-50 mt-sm w-56 rounded-card border border-rule bg-surface p-sm shadow-md">
+          <li className="border-b border-rule py-xs">
+            <p className="text-small text-ink">{displayName}</p>
+            <p className="text-tiny text-ink-muted">{displayEmail}</p>
+          </li>
+          <li className="py-xs text-small text-ink-muted">
+            角色：{displayRole}
+          </li>
+        </ul>
+      ) : null}
+    </div>
+  );
+}