Present: what we are building

One file per plan being built now, as Plan-YYYYMMDD - <title>.md.

A plan is written in plan mode, approved before work starts, and edited as reality changes. Its life ends at its PR: the plan becomes the PR description and the file is deleted in that same PR (CLAUDE.md, Branch). The merged PR is then the design record, and it carries the diff the plan describes.

A file here that no longer has work behind it is either finished, and belongs in its PR, or abandoned, and belongs deleted.