feat: hierarchical notebook system - trash, selectors, breadcrumb, sidebar tree

- Schema: soft delete with trashedAt on Notebook model
- API: PATCH/GET notebooks support trashedAt filtering with cascade
- Sidebar: recursive tree rendering with collapse/expand, visual guides, hover actions
- HierarchicalNotebookSelector: portal-based dropdown with search, breadcrumbs, dropUp support
- AI chat: context selector with Toutes mes notes + notebook selector
- Agent detail: flat selects replaced with HierarchicalNotebookSelector
- Breadcrumb: notebook path display on home page
- Trash view: card grid with countdown, restore/permanent delete
- CSS: design tokens (ink, paper, blueprint, concrete, etc.)
- Types: parentId, trashedAt added to Notebook interface

memento-note/app/(main)/trash/page.tsx

@@ -1,21 +1,13 @@
-import { getTrashedNotes } from '@/app/actions/notes'
-import { MasonryGrid } from '@/components/masonry-grid'
-import { TrashHeader } from '@/components/trash-header'
-import { TrashEmptyState } from './trash-empty-state'
+import { getTrashedNotes, getTrashedNotebooks } from '@/app/actions/notes'
+import { TrashClient } from './trash-client'
 
 export const dynamic = 'force-dynamic'
 
 export default async function TrashPage() {
-  const notes = await getTrashedNotes()
+  const [notes, notebooks] = await Promise.all([
+    getTrashedNotes(),
+    getTrashedNotebooks(),
+  ])
 
-  return (
-    <main className="container mx-auto px-4 py-8 max-w-7xl">
-      <TrashHeader noteCount={notes.length} />
-      {notes.length > 0 ? (
-        <MasonryGrid notes={notes} isTrashView />
-      ) : (
-        <TrashEmptyState />
-      )}
-    </main>
-  )
+  return <TrashClient initialNotes={notes} initialNotebooks={notebooks} />
 }