Poke Isles Pokemon Sizes 1.3.10

- Corrected the class-file retention metadata for all new shoulder mixins.
- TeacupPlayerPartyStoreMixin, TeacupShoulderedStateMixin, and PokemonOnShoulderRendererMixin now expose @Mixin through RuntimeInvisibleAnnotations as Sponge Mixin requires.
- Kept shoulder mixins mandatory so failures cannot be silently ignored.
- Retains the 1.3.9 teacup eligibility, shoulder-state validation, and fallback rendering logic.
