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/suggest-notebook/route.ts

@@ -1,6 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server'
 import { auth } from '@/auth'
 import { notebookSuggestionService } from '@/lib/ai/services/notebook-suggestion.service'
+import { hasUserAiConsent } from '@/lib/consent/server-consent'
 
 export async function POST(req: NextRequest) {
   try {
@@ -9,6 +10,10 @@ export async function POST(req: NextRequest) {
       return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
     }
 
+    if (!(await hasUserAiConsent())) {
+      return NextResponse.json({ error: 'ai_consent_required' }, { status: 403 })
+    }
+
     const body = await req.json()
     const { noteContent, language = 'en' } = body