feat(documents): hub page with tabs, filters, and live counts

Replaces /documents with the Phase A hub: tabs (All/Awaiting them/
Awaiting me/Completed/Expired) backed by per-tab counts via a new
hub-counts endpoint, signature-only chip, type filter, expandable
signer rows, and real-time invalidation across the eight document
socket events. listDocuments grew tab/watcher/signatureOnly/sent-window
filters; the legacy file browser moved to /documents/files where the
sidebar already linked.

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

src/app/(dashboard)/[portSlug]/documents/new/page.tsx

@@ -0,0 +1,24 @@
+import Link from 'next/link';
+import { Button } from '@/components/ui/button';
+import { PageHeader } from '@/components/shared/page-header';
+
+interface PageProps {
+  params: Promise<{ portSlug: string }>;
+}
+
+export default async function NewDocumentPage({ params }: PageProps) {
+  const { portSlug } = await params;
+  return (
+    <div className="flex flex-col gap-4">
+      <PageHeader
+        title="New document"
+        description="The create-document wizard ships in PR6 of the Phase A rollout."
+        actions={
+          <Button asChild variant="outline">
+            <Link href={`/${portSlug}/documents`}>Back to documents</Link>
+          </Button>
+        }
+      />
+    </div>
+  );
+}