player setting global supply w/o ownership of PCs fails without user-facing warning

[rsek]

this isn't illogical, but in our context it's not the most intuitive behaviour.

overriding foundry permissions seems fraught. ideally, we'd be able to flag certain properties as editable by anyone.

or, we could have the shared supply object live in world-level settings? to me, this seems like the most straightforward way to model it. that would make it subject to the SETTINGS_MODIFY user permission, though -- not specially intuitive.

aside: given the current state of FVTT, think 1 party = 1 world might simplify a lot of things for us in the long run. see #912