- Extract getDefaultCoreConfig, applyDefaultCoreConfig, and
isMissingOrUnresolvedCoreConfigValue into core-config-defaults.js
- Memoize YAML parsing with clearable cache for testing
- Use prompts.log.warn instead of console.warn for error logging
- Guard process.cwd() with try/catch in --yes path
- Centralize handler.js placeholder replacement via shared defaults
- Add tests for backfill logic and custom handler shared defaults