Add CI job to verify harness evolution results don't become stale

[OnePunchMonk]

Summary

Once harness evolution results are real (#19), we need CI to ensure they stay verified and don't drift from committed state. This prevents accidental staleness of the README's key claims.

Related

• Blocks: Nothing
• Depends on: Make 6-epoch harness evolution results real & reproducible #19 (must have real results to verify against)
• Relevant docs: .github/workflows/ci.yml

Task

Extend .github/workflows/ci.yml harness-verification job to:

1. Run scripts/harness_evolution_6_epochs.py in CI
2. Compare output JSON against committed versions
3. Fail the job if results drift beyond a tolerance (e.g., >1% Sharpe change)
4. Alternatively: add a make verify-results / script for maintainers to run before updating README claims

Files to Modify

• .github/workflows/ci.yml — Add verification job
• Optional: Makefile or scripts/verify-results.sh — Maintenance script

Acceptance Criteria

• CI job runs evolution scripts on every PR
• Job fails if results drift materially
• Job passes if results match or are intentionally updated
• Documentation added on how to update results intentionally

Notes

This enforces the 'no lying in README' property going forward by catching accidental staleness.