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/app/(main)/settings/mcp/mcp-settings-header.tsx

@@ -0,0 +1,22 @@
+'use client'
+
+import { useLanguage } from '@/lib/i18n'
+import { SettingsHelpBox } from '@/components/settings/settings-help-box'
+
+export function McpSettingsHeader() {
+  const { t } = useLanguage()
+
+  return (
+    <SettingsHelpBox
+      title={t('mcpSettings.helpBox.title')}
+      defaultOpen={true}
+      steps={[
+        { text: t('mcpSettings.helpBox.step1') },
+        { text: t('mcpSettings.helpBox.step2') },
+        { text: t('mcpSettings.helpBox.step3') },
+        { text: t('mcpSettings.helpBox.step4'), link: { label: t('mcpSettings.helpBox.step4Link'), href: 'https://modelcontextprotocol.io/docs' } },
+        { icon: '⚡', text: t('mcpSettings.helpBox.step5') },
+      ]}
+    />
+  )
+}