docs: update CLAUDE.md with comprehensive codebase guide#803

dmclane1B wants to merge 3 commits into

pollen-robotics:mainpollen-robotics/reachy_mini:mainfrom

dmclane1B:claude/claude-md-mlbb8nq1gcaczdxe-kKO4Qdmclane1B/reachy_mini:claude/claude-md-mlbb8nq1gcaczdxe-kKO4QCopy head branch name to clipboard