Captures session state at the natural pause point: design spec
approved, no implementation started. Supersedes the scaffold-only
handoff (which described an empty-dir state).
Validated 80/100 by validate_handoff.py. The 4 file-not-found
warnings reference scripts/* that are intentionally unwritten —
they are the next session's deliverables per the spec.
Resume next session with writing-plans skill against the spec at
sethlabels-docs/specs/2026-04-29-packaging-design.md.
