Close a batch

1. Check that every unit of batches/NN/ has a last review round that says "approved". If not, list the ones that wait and stop.
2. Move what is open: proposed units stay in proposed/ (tell the user they wait for approval); open items in the report go to a later unit, LATER.md or USER.md. Nothing open stays only in the folder.
3. Time log: every unit and change round has a complete row (times, effort before and after, the wrong factor, stats).
4. Background: when the last unit of a topic is done, remove its section from BACKGROUND.md.
5. Mark the batch done in BATCHES.md, then git rm -r batches/NN and commit Done: Batch N with the main commit. Git keeps the units, reviews and report.
6. Calibrate every 2 batches: compare agent time per effort level and the factors that were wrong most often; propose changes to EFFORT.md to the user.
7. Report: the batch is closed, what moved where, what waits for approval, the passes now due (PASSES.md; run them with /passes before the next batch), and the next batch's 5 units.