Implementation plan and status

Completion checklist

• Every specification rule affected by this RFD is accounted for in the Design chapters changed with the proposal; accepted revisions are reflected there and referenced from this plan.
• The chapter's Current Status section links the evidence which establishes each implemented anchor and states any remaining gap.
• Every genuinely cross-cutting choice is recorded or updated in Architecture Decisions; feature-local rationale remains in this RFD.
• The affected roadmap slice and RFD status indexes are updated.