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/reformulate/route.ts

@@ -3,6 +3,7 @@ import { auth } from '@/auth'
 import { paragraphRefactorService } from '@/lib/ai/services/paragraph-refactor.service'
 import { getAISettings } from '@/app/actions/ai-settings'
 import { checkEntitlementOrThrow, QuotaExceededError, incrementUsageAsync } from '@/lib/entitlements'
+import { hasUserAiConsent } from '@/lib/consent/server-consent'
 
 export async function POST(request: NextRequest) {
   try {
@@ -12,6 +13,10 @@ export async function POST(request: NextRequest) {
       return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
     }
 
+    if (!(await hasUserAiConsent())) {
+      return NextResponse.json({ error: 'ai_consent_required' }, { status: 403 })
+    }
+
     // Respect user's paragraphRefactor toggle (Assistant IA)
     const userSettings = await getAISettings(session.user.id)
     if (userSettings.paragraphRefactor === false) {