Past releases had a debug-only assertion that 25 was sufficient, but
then dynamically allocated enough storage for larger models as needed.
Commit 22a34809ee ("Move interpreter g3s_lrgb onto stack") added a
hard limit of 25, but did not detect attempts to exceed this. Custom
models that exceeded 25 would cause a stack buffer overwrite and likely
crash. Raise the limit to 64 and add sanity checking to refuse to
render models that exceed MAX_POINTS_PER_POLY.
Fixes: 22a34809ee ("Move interpreter g3s_lrgb onto stack")
79e4e0a628