docs(readme): add loop evolution section covering 13→19 hat additions

feat(loop): add codebase audit feature to Marge and Nelson

feat(loop): add security, compliance, and release gate hats; evidence-gated curation

fix(ralph): structured event payloads to prevent infinite loops

fix: default_publishes must be string, not array

Add ralph-factcheck loop for spec validation against official docs

chore: remove auto_merge and parallel features from all ralph configs

fix(observe): Grandpa can now diagnose and fix GitHub Actions failures

fix(observe): add build infrastructure diagnosis to Grandpa

Update agent models: add coder, change lite to qwen3-coder-next, document choices

feat(loop): add auto-merge support and integrate ralph task tracker

fix(marge): curate PROMPT.md first, then pick by priority from full backlog

docs: add blog post link to README

docs: rewrite README with setup guide, 16-hat table, and loop variants

feat: genericize grandpa-loop for any project