fix(audit): nettoyage accès, garde-fous build, unification quotas

Semaine 1 — fuites et accès :
- /archive rendu accessible via sidebar (était invisible)
- Suppression pages orphelines : /chat, /graph, /support, test-title-suggestions
- Fixes i18n : search-modal (clé non interpolée), sidebar tooltips, export PDF
- 15 locales mises à jour

Semaine 2 — garde-fous :
- 8 erreurs TS fixees → ignoreBuildErrors: false (build type-safe)
- reactStrictMode: true (dev-only, zero impact prod)
- reserveUsageOrThrow → wrapper deprecie vers reserveAiUsageOrThrow
- auth-guard.ts : requireAuthOrResponse() + requireAdminOrResponse()

Tests 212/212 | Lint 0 erreur | Build OK | tsc 0 erreur

memento-note/app/api/ai/auto-labels/route.ts

@@ -19,6 +19,7 @@ export async function POST(request: NextRequest) {
         { status: 401 }
       )
     }
+    const userId = session.user.id
 
     // GDPR AI Consent check
     if (!(await hasUserAiConsent())) {
@@ -61,12 +62,12 @@ export async function POST(request: NextRequest) {
     }
 
     const suggestions = await withAiQuota(
-      session.user.id,
+      userId,
       'auto_tag',
       () =>
         autoLabelCreationService.suggestLabels(
           notebookId,
-          session.user!.id,
+          userId,
           language,
         ),
       { lane: 'tags' },