Codebase Health Refactoring Sprint overview

Executes focused refactoring sprints to improve codebase health metrics — identifying hotspots using code churn and complexity analysis (cyclomatic, cognitive), prioritizing refactoring targets by coupling with high-change-frequency modules, executing safe automated refactoring operations (extract method, rename, move) with comprehensive test validation, measuring before/after complexity scores and build time impact, and updating architecture documentation to reflect structural changes. Produces refactoring proposals with risk assessment, complexity delta reports, and architectural fitness function trends. Excludes feature development.