Add trust features: history, trash, export, and collection sharing

Implement Notion-like upgrade phase 4: append-only page revisions with restore-as-a-new-version; recoverable bookmark/page/collection deletions whose restores never resurrect public flags or shares; owner-scoped JSON export; and explicit, revocable read-only collection sharing with owner-only mutations and no transitive third-party bookmark leaks. Add migration 009, API/docs, integration coverage, and page/collections/trash UI.

web/app/(app)/trash/page.tsx

@@ -0,0 +1,7 @@
+import { TrashClient } from './client'
+
+export const dynamic = 'force-dynamic'
+
+export default function TrashPage() {
+  return <TrashClient />
+}