Close Week 4 with production readiness gates

[utkarshp845]

Summary

• add a Week 4 production-readiness review with explicit go/no-go decisions
• add make validate for builds, tests, lint, and deterministic assistant evaluations
• enforce the assistant evaluation corpus in pull-request CI
• update the roadmap, README, contribution workflow, and build log

Validation

• git diff --check
• docker compose config -q
• Full container validation was not run locally because the Docker Desktop engine was unavailable; CI runs tests, lint, and evaluations.