Add coreerr.E() and coreio.Local conventions to CLAUDE.md coding
standards. Wrap two raw os.OpenFile/io.Copy errors in extractTarball
with coreerr.E for consistent error context.
Coverage: logging 86%, node 86%, levin 87%, ueps 92%.
No fmt.Errorf or os.ReadFile/os.WriteFile in production code.
Co-Authored-By: Virgil <virgil@lethean.io>
Replace internal task tracking (TODO.md, FINDINGS.md) with structured
documentation in docs/. Trim CLAUDE.md to agent instructions only.
Co-Authored-By: Virgil <virgil@lethean.io>