Add advanced test coverage and visualization tools

[Nikita-Filonov]

This PR adds a set of open-source tools focused on measuring and visualizing test coverage across different testing layers:

• Tests Coverage Tool — gRPC test coverage analyzer.
• Swagger Coverage Tool — API test coverage tool based on Swagger/OpenAPI.
• UI Coverage Tool — innovative in-browser visualization of real UI test coverage (not screenshots).
• Load Testing Hub Panel — sleek dashboard to visualize load testing results.

All tools are framework-agnostic, lightweight, and designed to be integrated into real-world pipelines.

Let me know if you'd like me to break it into separate PRs or adjust descriptions.