docs(rag): consolidated roadmap for the 5 next-step moves (#2)

After the Shape 2 validation prototype (+40 pts P@1 on
bug-predict, confirmed on security-audit), the RAG
improvement path has five concrete moves:

1. Promote 0.7.0 spec from draft to in-progress
2. Add Shape 2 fixtures as 0.7.0 Task 6
3. Rerun attune-rag golden benchmark after 0.7.0 ships
4. Reconsider fastembed v0.2.0 priority (decision matrix
   pre-committed before the rerun so we cannot move the
   goalposts)
5. Capture the summary-channel-dead-weight lesson in
   attune-ai CLAUDE.md

Documents sequencing, success criteria, and open risks
including mutual competition once all features are
polished, industry-terminology gaps in the polish prompt,
and fixture maintenance burden.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: silversurfer562