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/lib/ai/services/notebook-wizard.service.ts

@@ -251,8 +251,8 @@ Rules:
 
     const raw = await provider.generateText(prompt)
     const parsed = this.parseJsonObject(raw)
-    const titles = Array.isArray(parsed?.titles)
-      ? parsed.titles.map((t: unknown) => String(t || '').trim()).filter(Boolean).slice(0, count)
+    const titles: string[] = Array.isArray(parsed?.titles)
+      ? (parsed.titles as unknown[]).map((t) => String(t || '').trim()).filter(Boolean).slice(0, count)
       : []
     while (titles.length < count) {
       titles.push(lang === 'fr' ? `Chapitre ${titles.length + 1}` : `Chapter ${titles.length + 1}`)