[pt] Localize JavaScript documentation pages (api, benchmarks, examples, registry)

[ANAMASGARD]

FIXES :- #8385 (partial - 4 of 8 main files completed)

Description

Translated the following JavaScript documentation files from English to Portuguese:

• content/en/docs/languages/js/api.md
• content/en/docs/languages/js/benchmarks.md
• content/en/docs/languages/js/examples.md
• content/en/docs/languages/js/registry.md

This is part of the Portuguese localization effort tracked in #8385.

Checklist

• [x] Read the contribution guidelines
• [x] Followed the Portuguese localization style guide
• [x] Preserved code examples and formatting
• [x] Maintained YAML frontmatter structure
• [x] Used natural Brazilian Portuguese translations