Port and register agent skill: browser-testing-with-devtools from @addyosmani/agent-skills

[nnoce14]

Task

Port the skill browser-testing-with-devtools from @addyosmani/agent-skills and integrate it into this repository for Copilot agents usage.

Acceptance Criteria

• The skill is ported and added to the appropriate skills directory following CellixJS's agent skill registration process.
• Skill is usable for Copilot coding agents in CellixJS (mandatory). Compatibility with other coding agents is desirable but optional.
• The skill index file at .agents/skills/README.md is updated to include the new skill and relevant metadata.
• All relevant instructions, manifest, and usage documentation from the source skill are included or adapted as appropriate.
• The implemented skill must conform to the repository architecture and quality standards (see ADR-0019).
• Basic tests or a working example are provided for the ported skill, if provided upstream.
• A Chrome DevTools MCP server is provisioned/configured as part of the skill so the browser-testing flows function end-to-end and reliably in CI and developer environments.
• Verify the Anthropic-provided package used by the upstream skill functions correctly with multiple model backends (i.e., not limited to Claude). Document any compatibility requirements or limitations. The final implementation must work for Copilot agents (and should not rely on a runtime coupling to Claude-only features).
• Provide usage instructions for running the MCP server locally and in CI, plus any environment or secrets configuration required.
• If upstream code is adapted, include attribution and clearly document changes in the skill README.

Notes

• The MCP server requirement is to ensure real DevTools protocol interactions for end-to-end testing and realistic agent behaviors.
• The Anthropic package verification is to avoid shipping a skill that only works with a single hosted model; Copilot agents must be supported.
• Where appropriate, include a small example workspace or test demonstrating a Copilot agent using the skill against the MCP server.

References

• Source skill folder
• SKILL.md spec