chore: end-to-end integration smoke test

[p1gushka]

Description

Manually verify the full cycle works. Not a code task — checklist to run through locally.

Tasks

• Build: ./mvnw package
• Start Agent, confirm "Agent listening on port 7070" in logs
• Run Master with --url=https://httpbin.org/get --rps=5 --duration=20 --agent=localhost:7070
• Confirm live stats lines appear in Master console every second
• Confirm report file is created after test finishes
• Repeat with --rps=50 to verify virtual threads handle higher load