docs: update LangDB links in observability documentation
- Removed references to the AI Gateway features in both English and Portuguese documentation.
- Updated the Model Catalog links to point to the new app.langdb.ai domain.
- Ensured consistency across both language versions of the documentation.
* docs: add pt-br translations
Powered by a CrewAI Flow https://github.com/danielfsbarreto/docs_translator
* Update mcp/overview.mdx brazilian docs
Its en-US counterpart was updated after I did a pass,
so now it includes the new section about @CrewBase
