Monthly clean-up: close stale items and re-score open risks

The weekly review keeps the log current. This keeps it short.

1. Close anything resolved. A log full of dead entries is one people stop reading
2. Re-score every open risk. Probability moves as a project progresses, and a risk scored in March is usually wrong by June
3. Find open items with a Last Reviewed date more than a month old and either work them or close them
4. Check every dependency still has a live owner on the other side. People change roles and nobody tells the project