Add performance monitoring for each PR

[golobitch]

To ensure that performance does not degrade with new changes, we should add performance monitoring to the CI pipeline. The goal is to run a performance script with each PR and report the results directly in the PR as a comment. If the TPS metric fails below a threshold (eg 5 TPS) the build should fail

Context

• Performance should be monitored continuously to maintain quality
• Initial implementation could use a k6 script to measure and report performance metrics such as req/s and iter/s
• Fetching the TPS metric directly from Prometheus is worth exploring but might be more involved

Acceptance Criteria

• Add a k6 performance script to the CI pipeline
• Execute the script for every PR and print the results as a comment in PR

Tasks

• integrate the performance script into the CI pipeline and ensure it runs with each PR
• add logic to post the script results as a comment in the PR