fix(quotas): unifier le décompte IA (BYOK, rollback) et combler les fuites

Centralise la réserve via ai-quota, corrige admin unavailable (-1), brancher les routes sans quota et le host-pays brainstorm, avec usage-meter élargi, noms de clusters, MCP et ajustements dashboard/insights.

Co-authored-by: Cursor <cursoragent@cursor.com>

memento-note/components/settings/billing-history.tsx

@@ -112,7 +112,7 @@ export function BillingHistory() {
 
       {error && (
         <p className="text-xs text-rose-500 text-center py-4">
-          Impossible de charger l'historique de facturation.
+          {t('billing.fetchInvoicesFailed')}
         </p>
       )}
 
@@ -152,7 +152,7 @@ export function BillingHistory() {
                         target="_blank"
                         rel="noreferrer"
                         className="inline-flex items-center justify-center p-2 rounded-lg text-concrete hover:text-brand-accent hover:bg-brand-accent/10 transition-all"
-                        title="Download PDF"
+                        title={t('billing.downloadPdf')}
                       >
                         <Download size={14} />
                       </a>