feat(notes): liens internes, onglet Réseau, living blocks et consentement IA

Rend les liens entre notes visibles et persistants (sync NoteLink au save, auto-save, graphe réseau rafraîchi), ajoute living blocks, Memory Echo, recherche globale, consentement IA explicite et consolide les prototypes design en architectural-grid.

Co-authored-by: Cursor <cursoragent@cursor.com>

memento-note/app/api/ai/notebook-summary/route.ts

@@ -1,6 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server'
 import { auth } from '@/auth'
 import { notebookSummaryService } from '@/lib/ai/services'
+import { hasUserAiConsent } from '@/lib/consent/server-consent'
 
 /**
  * POST /api/ai/notebook-summary - Generate summary for a notebook
@@ -16,6 +17,13 @@ export async function POST(request: NextRequest) {
       )
     }
 
+    if (!(await hasUserAiConsent())) {
+      return NextResponse.json(
+        { success: false, error: 'ai_consent_required' },
+        { status: 403 }
+      )
+    }
+
     const body = await request.json()
     const { notebookId, language = 'en' } = body