Add agenttrace

[luoyuctl]

Summary

• Add agenttrace to the English command-line tools section
• Keep the description concise and aligned with the existing format

Validation

• git diff --check
• gh repo view luoyuctl/agenttrace --json nameWithOwner,url,description,stargazerCount,pushedAt

Note: I updated i18n/README.en.md following the repository contribution guide for adding a new tool.

[luoyuctl]

Refreshed this PR by resetting the commit author to the GitHub noreply identity. Validation: git diff --check upstream/main...HEAD. Current PR state is CLEAN/MERGEABLE with no checks configured.