perf(ci): speed up functional tests with parallel execution

[AbirAbbas]

Summary

• Add pytest-xdist for parallel test execution (-n auto)
• Reduce health check timing from 120s max to 30s max wait
• Control plane typically starts in ~10-15s, so 30s provides sufficient headroom

Why these changes are safe

1. No cache involvement - These optimizations don't touch Docker layer caching, so there's no risk of mysterious cache-related failures

2. Clear failure modes:

   • If health check times out → clear error message: "Control plane failed to become ready"
   • If tests have parallelism issues → tests fail with clear names, easy to identify

3. Test logic unchanged - Same tests, same assertions, just run in parallel

Expected savings

Optimization	Time Saved
Parallel test execution	~20-30s
Faster health check	~15-30s
Total	~30-60s

Risk assessment

Change	Risk	Mitigation
pytest-xdist	Low - possible race conditions	Tests run in isolated containers with fresh state
Health check timing	None	Clear timeout error if exceeded

Test plan

• CI functional tests pass for both local and postgres modes
• Verify parallel execution in CI logs (look for [gw0], [gw1], etc.)
• Compare CI timing before/after

🤖 Generated with Claude Code