feat: isolate all four portals with route groups + polished design system

Fix blank /org/login (and /admin/login): the guarded portal layout was
wrapping its own login route, rendering null when unauthenticated. Move
each portal's authed pages into a (authed)/(chapter) route group so login
pages live outside the guard.

Structure:
- app/(chapter)/* — chapter admin pages + guarded layout (was root-level)
- app/org/(authed)/* — org pages + guarded layout; /org/login now free
- app/admin/(authed)/* — admin pages + guarded layout; /admin/login free
- Root layout slimmed to providers only (no shared sidebar)
- Convert moved files' relative imports to @/app alias

Design system:
- PortalShell: shared sidebar shell (brand mark, themed active nav with
  accent bar, avatar dropdown user menu, loading skeletons)
- portal-theme.ts: per-portal theme tokens (violet/slate/blue/emerald)
- PortalLoginShell redesigned: two-column with gradient branding panel,
  dotted pattern, value-prop highlights, built-in back link
- New shadcn components: Avatar, DropdownMenu, Skeleton
- Move shared DraftCard to _components/draft-card.tsx (used by 2 portals)
- Portal selector: remove Super Admin card, icon tiles, hover lift
- All 4 login pages use react-hook-form + Zod + themed shell
- Member nav restored to full 11-section list with icons

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

apps/web/app/org/(authed)/page.tsx

@@ -0,0 +1,63 @@
+'use client';
+
+import { useEffect, useState } from 'react';
+import { useRouter } from 'next/navigation';
+import Link from 'next/link';
+import { useOrgAdmin } from '@/app/_lib/org-admin-context';
+
+export default function OrgDashboardPage() {
+  const { orgAdmin, loading } = useOrgAdmin();
+  const router = useRouter();
+  const [data, setData] = useState<any>(null);
+
+  useEffect(() => {
+    if (loading) return;
+    if (!orgAdmin) { router.replace('/org/login'); return; }
+    fetch('/api/org/dashboard')
+      .then((r) => r.ok ? r.json() : null)
+      .then((d) => setData(d))
+      .catch(() => {});
+  }, [orgAdmin, loading, router]);
+
+  if (loading || !orgAdmin) return <p className="text-gray-500 p-6">Loading...</p>;
+
+  return (
+    <div>
+      <h1 className="text-2xl font-bold mb-1">{orgAdmin.organization?.name ?? 'Organization'}</h1>
+      <p className="text-sm text-gray-500 mb-6">{data?.chapterCount ?? '—'} chapters</p>
+
+      <div className="grid gap-4">
+        {(data?.chapters ?? []).map((chapter: any) => (
+          <div key={chapter.id} className="bg-white rounded-xl border p-5 flex items-center justify-between">
+            <div>
+              <Link href={`/org/tenants/${chapter.id}`} className="font-medium text-blue-600 hover:underline">
+                {chapter.name}
+              </Link>
+              <p className="text-xs text-gray-500 mt-1">{chapter.slug}</p>
+            </div>
+            <div className="flex gap-6 text-sm text-right">
+              <div>
+                <p className="font-medium">{chapter.messageCount}</p>
+                <p className="text-xs text-gray-400">messages</p>
+              </div>
+              <div>
+                <p className="font-medium">{chapter.memberCount}</p>
+                <p className="text-xs text-gray-400">members</p>
+              </div>
+              <div>
+                <p className="font-medium">{chapter.adminCount}</p>
+                <p className="text-xs text-gray-400">admins</p>
+              </div>
+              <span className={`self-center text-xs font-medium px-2 py-1 rounded-full ${chapter.isActive ? 'bg-green-100 text-green-700' : 'bg-red-100 text-red-700'}`}>
+                {chapter.isActive ? 'Active' : 'Inactive'}
+              </span>
+            </div>
+          </div>
+        ))}
+        {data && data.chapters.length === 0 && (
+          <p className="text-gray-400">No chapters yet. <Link href="/org/tenants" className="text-blue-600 hover:underline">Add a chapter</Link>.</p>
+        )}
+      </div>
+    </div>
+  );
+}