feat(ui): yacht detail page with header, tabs, ownership history

Implements Task 5.3: server page passes yachtId to a client YachtDetail,
which fetches via TanStack Query and renders the shared DetailLayout with
Overview / Ownership History / Interests / Reservations / Notes / Tags
tabs. Header shows name, dimensions, polymorphic owner link, status badge,
and Edit / Transfer / Archive actions. Transfer is a stub dialog pending
Task 5.5; Notes tab is a placeholder because NotesList does not yet support
entityType='yachts'.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/(dashboard)/[portSlug]/yachts/[yachtId]/page.tsx

@@ -0,0 +1,16 @@
+import { YachtDetail } from '@/components/yachts/yacht-detail';
+import { auth } from '@/lib/auth';
+import { headers } from 'next/headers';
+
+interface YachtDetailPageProps {
+  params: Promise<{ yachtId: string }>;
+}
+
+export default async function YachtDetailPage({ params }: YachtDetailPageProps) {
+  const { yachtId } = await params;
+
+  const session = await auth.api.getSession({ headers: await headers() });
+  const currentUserId = session?.user?.id;
+
+  return <YachtDetail yachtId={yachtId} currentUserId={currentUserId} />;
+}