Add Agent Teams AI to AI Tools

[777genius]

Types of Changes

• New addition to list
• Fixing bug in existing item in list
• Removing item from list
• Changing structure (organization) of list

Proposed Changes

1. Add Agent Teams AI to AI Tools in the English, Chinese, Japanese, and Korean lists.
2. Describe it as an open-source desktop app for coordinating autonomous AI coding agents.
3. Link the product site and its AGPL-3.0 source repository.

The current v2.8.0 release provides macOS downloads for both Apple Silicon and Intel.

Disclosure: I maintain Agent Teams AI.

PR Checklist

• I have read the CONTRIBUTING guide
• I have explained why this PR is important
• I have added necessary documentation
• I searched issues, pull requests, and all four README files for duplicates
• I kept one concise sentence and alphabetical placement in each language

Validation

• git diff --check
• Confirmed exactly one Agent Teams AI entry in each of the four README files
• Confirmed the product site, source repository, license, and macOS release assets