feat: add decisions log to Ralph completion protocol

Update README.md

Add testing guardrails and update README architecture diagram

docs: redesign architecture diagram for GitHub rendering

docs: add architecture diagram to README

simplify: Amelia verdicts to retry/halt only (sequential pipeline)

fix: Amelia retry re-enters inner loop, skip doesn't halt pipeline

feat: continuation model — re-launch on max-turns if progress was made

fix: nested session guard, raise max-turns, halt on block

Initial release: Ralph Wiggum sequential story executor for Claude Code