feat: show tenancy scope (Org → Chapter) in chapter & member portals

Surface where the logged-in user sits in the hierarchy via a ScopeCard
in the sidebar, below the brand mark.

API:
- Enrich chapter login/me responses with tenantName + organization
  (LoginResponse.admin, AdminProfile types updated)
- Add GET /my/scope returning member's chapter + organization

Web:
- ScopeCard component (Organisation row + Chapter row, themed icons)
- Chapter portal: scope from auth context, blue accent
- Member portal: scope fetched server-side in layout, emerald accent
- PortalShell gains a `scope` slot rendered under the brand

Org and admin portals intentionally omit it — org IS the scope, admin is
platform-wide.

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

apps/web/app/my/layout.tsx

@@ -1,14 +1,31 @@
-import { getMemberToken } from '../_lib/api';
+import { getMemberToken, getApiBaseUrl } from '../_lib/api';
 import { redirect } from 'next/navigation';
 import { MemberNav } from './member-nav';
 
+interface MemberScope {
+  member: { displayName: string | null };
+  chapter: { id: string; slug: string; name: string };
+  organization: { id: string; slug: string; name: string } | null;
+}
+
+async function fetchScope(token: string): Promise<MemberScope | null> {
+  const res = await fetch(`${getApiBaseUrl()}/my/scope`, {
+    headers: { Authorization: `Bearer ${token}` },
+    cache: 'no-store',
+  }).catch(() => null);
+  if (!res || !res.ok) return null;
+  return (await res.json()) as MemberScope;
+}
+
 export default async function MemberLayout({ children }: { children: React.ReactNode }) {
   const token = await getMemberToken();
   if (!token) redirect('/member-login');
 
+  const scope = await fetchScope(token);
+
   return (
     <div className="flex h-screen overflow-hidden">
-      <MemberNav />
+      <MemberNav scope={scope} />
       <main className="flex-1 overflow-auto bg-muted/30">
         <div className="p-6 lg:p-8 max-w-6xl mx-auto w-full">{children}</div>
       </main>