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/rich-text-editor.tsx

@@ -2005,7 +2005,7 @@ function SlashCommandMenu({ editor, onInsertImage, onSuggestCharts }: { editor:
         }),
       })
       const data = await res.json()
-      if (!res.ok) { toast.error(data.error || 'Erreur'); return }
+      if (!res.ok) { toast.error(data.errorKey ? t(data.errorKey) : (data.error || 'Erreur')); return }
       let html = data.reformulatedText || data.text || ''
       // Clean up excessive whitespace
       html = html