30b903b6c0
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