Drop the work log from TODO.md; keep only open work (closes #255)

TODO.md held a dated log of finished steps, merge history and accounts
of earlier live-feed runs. It now holds the Status line, the open Next
Step and an empty Future Steps. README "TODO" no longer says the file
lists the steps done.

Model: opus-5-5

README.md

@@ -1100,8 +1100,7 @@ calls one of them. The scripts:
 
 ## TODO
 
-`TODO.md` holds the working list: the next step, the steps done and the steps
-planned.
+`TODO.md` holds the working list: the next step and the steps planned.
 
 ## License