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/chat/route.ts

@@ -5,6 +5,7 @@ import { getSystemConfig } from '@/lib/config'
 import { semanticSearchService } from '@/lib/ai/services/semantic-search.service'
 import { prisma } from '@/lib/prisma'
 import { auth } from '@/auth'
+import { hasUserAiConsent } from '@/lib/consent/server-consent'
 import { loadTranslations, getTranslationValue, SupportedLanguage } from '@/lib/i18n'
 import { toolRegistry } from '@/lib/ai/tools'
 import { checkEntitlementOrThrow, QuotaExceededError, incrementUsageAsync } from '@/lib/entitlements'
@@ -49,6 +50,14 @@ export async function POST(req: Request) {
   }
   const userId = session.user.id
 
+  // GDPR AI Consent check
+  if (!(await hasUserAiConsent())) {
+    return new Response(JSON.stringify({ error: 'ai_consent_required' }), {
+      status: 403,
+      headers: { 'Content-Type': 'application/json' },
+    })
+  }
+
   // 1.5 Quota check (per-provider BYOK bypass — only when BYOK will be used for resolved provider)
   try {
     const sysConfigEarly = await getSystemConfig()