I am out of time until next weekend. I see three important-ish things left to do:
1) We load up TCRS data for you at login (or ascension). So, what happens when KoL adds new items which are not in our saved data? Should be easy enough to handle: "derive" will only update items it does not already have stored. So, "load" + "derive" is essentially "update".
We should add an "update" (and "save" if necessary) step in part of our load sequence. We are certainly willing to update our data files if people keep sharing as new items are added. Regardless, an "update" step is not (for now) especially grievous. It will become more burdensome as hundreds and thousands of new items are added beyond our published data, but years from now, if you run TCRS out of Standard, you will wantt the new data.
2_ We need to implemt the "resetModifiers" method in TCRSDatabase. We call it when you free the king (to undo all the TCRS adjustments to items), but should probably do it .... somewhere .. when you log out (or when you log in without restarting KoLmafia, which I never do), so that the next character doesn't start out with munged items.
3) As part of "apply" (to be undone by "reset modifiers"), we need to replace all "gain_effect" methods for statuseffects that depend on "eat", "drink", "chew", or "use" to have exactly the methods which provide that grant that effect in TCRS. This is necessary for the maximizer to work with TCRS usable items.
As I said, I have no more time for this - but nothing is stopping others from looking at these issues.