feat: Stagger item categories for modder support

[RoyalFox2140]

Checklist

Required

• I wrote the PR title in conventional commit format.
• I ran the code formatter.
• I linked any relevant issues using github keyword syntax so it can be closed automatically.
• I have committed my changes to new branch that isn't main so it won't cause conflict when updating main branch later.

Purpose of change

We don't want stuff to overlap. Item categories were all 1 after the other. Modders couldn't put stuff where they want.

Describe the solution

I staggered every category by 3. Now you get 2 categories to inject between any other. Nothing changed under the hood

Mods can fight if they want, I'm not a cop but maybe try not to use categories unless you have to.

Describe alternatives you've considered

Suffering. Making others suffer by figuring out a code-based solution that lets users sort categories themselves.

Testing

Additional context

Someone should code it so users can organize their own categories, but I can't.

[RobbieNeko]

LGTM, very nice improved mod support.