docs: compact roadmaps and CLAUDE.md

Collapse the accumulated make_plan/preflight/exec_plan/phase changelog that
had ballooned all three living docs, keeping only current status, a short
milestone log, and the authoritative status tables. Full per-slice history
still lives in the plan dirs, codeops/_archive/, and git history.

- feature roadmap 829->160, portfolio 283->61, CLAUDE.md 386->160 lines
- move RD-15 and RD-12 from Pending to Done (they were complete but still
  listed pending, against the Update Protocol); Pending now = RD-18/13/14
- refresh the stale Current Position to reflect the RD-18 slice rollout
- CLAUDE.md: replace the RD-by-RD narrative with a roadmap pointer, tighten
  Commands + Project structure, prune stacked refresh comments to one

Author: gevik