Epic 13: Load Testing

[omatheusmesmo]

Only useful once resilience (Epic 4), observability (Epic 7), and infra (Epic 12) are in place — otherwise it just finds the obvious and you can't even see what happened.

Issues

• Set up k6 (or Gatling) with baseline scripts #78
• Run a baseline load test and capture current numbers #79
• Fix the bottlenecks the load test surfaces #80
• Add load testing as a CI/scheduled gate #81