Ci/tests coverage

[pepedinho]

This pull request updates the CI workflow to improve test diagnostics and add automated code coverage reporting. The most important changes are grouped below:

Test diagnostics improvements:

• Set RUST_BACKTRACE to full and RUST_LOG to debug when running cargo test to provide more detailed error logs during CI runs.

Code coverage integration:

• Added a new coverage job to the GitHub Actions workflow that installs Rust and Tarpaulin, runs code coverage analysis with cargo tarpaulin, outputs reports in both Lcov and HTML formats, and uploads the results as an artifact.
• Integrated the Codecov GitHub Action to upload the Lcov coverage report to Codecov, enabling coverage tracking and reporting for the project.

[codecov-commenter]

Welcome to Codecov 🎉

Once you merge this PR into your default branch, you're all set! Codecov will compare coverage reports and display results in all future pull requests.

ℹ️ You can also turn on project coverage checks and project coverage reporting on Pull Request comment

Thanks for integrating Codecov - We've got you covered ☂️