Everything a page needs: the home folder, the current state, and every passage.
The home folder: KIZUKI_HOME if set, otherwise ~/.kizuki.
KIZUKI_HOME
~/.kizuki
Every passage, by passage id.
The current state, rebuilt from the logs.
Today's date as YYYY-MM-DD, in the computer's time zone.
YYYY-MM-DD
Everything a page needs: the home folder, the current state, and every passage.