TODO.md holds only open work (closes #202)

Completed Steps, the dated log of finished work, is removed. The
Workflow says to delete Next Step once done instead of moving it there,
and Status no longer names the first release candidate. The README's
TODO section no longer says the file records what has been done.

Model: opus-5-5

README.md

@@ -445,8 +445,8 @@ says what it checks and what it cannot.
 
 ## TODO
 
-The to-do list is [TODO.md](TODO.md): where the work stands, the next step, the
-open work, and what has been done.
+The to-do list is [TODO.md](TODO.md): where the work stands, the next step and
+the open work.
 
 ## License