This change updates all size-related members within the `mjModel` struct from `int` to `mjtSize`. This allows MuJoCo to handle models with a larger number of elements. Corresponding changes were made to macros, function signatures, and I/O routines to accommodate the new `mjtSize` type.
PiperOrigin-RevId: 860144595
Change-Id: I701c6d607715d240766b6210a9773cd9e4258c59
This allows other modules to depend on functions such as FromRawPointer that previously were only defined in the _struct python module.
PiperOrigin-RevId: 745619670
Change-Id: I9f1af60cb665c00d853b7ca38201b37302d278af