fix: replace raw ai_consent_required code with translatable message and consent prompt

- Centralize AI consent 403 responses in server-consent helpers
- Return human-readable message + code + i18n errorKey from all AI APIs
- Update dashboard and AI clients to detect code/errorKey and translate
- Add consent.ai.requiredToast i18n keys (fr/en)

memento-note/components/notebook-summary-dialog.tsx

@@ -68,7 +68,7 @@ export function NotebookSummaryDialog({
       if (data.success && data.data) {
         setSummary(data.data)
       } else {
-        toast.error(data.error || t('notebook.summaryError'))
+        toast.error(data.errorKey ? t(data.errorKey) : (data.error || t('notebook.summaryError')))
         onOpenChange(false)
       }
     } catch (error) {