OK, this is the big one. We still keep using `#include` guards only
where we absolutely need to, but with each header now being valid in
isolation, this can now actually help *minimize* the length of each
translation unit's `#include` list. Turns out that after removing all
the duplicates, we only *actually* need to guard 29 headers across all
5 games.
Part of P0285, funded by [Anonymous] and iruleatgames.
Only seen in Mima's fight, but initialized for all non-final boss
fights. Also with explicit support for all 8 origin edges, not just the
top-right one used in Mima's fight… and an off-by-one error?!
Completes P0160, funded by Yanga.