update constants for `float`

mujoco has a number of [constants](https://mujoco.readthedocs.io/en/latest/APIreference/APIglobals.html#glnumeric) that were tuned for `double`. we should determine good default values that work for `float` and update mujoco warp's relevant constants to these values.

- [ ] [mjMINMU](https://github.com/google-deepmind/mujoco_warp/issues/942#issuecomment-3714388647): `mjMINMU` (=1e-5) does not prevent nans when using `float`
- [ ] [GJK tolerance](https://github.com/google-deepmind/mujoco_warp/pull/902#discussion_r2671395702): tolerance too small for float leading to failing test
- [ ] [solver tolerance override](https://github.com/google-deepmind/mujoco_warp/blob/2a7ad9cb2207e1cd4955392592cc41ab52bde99c/mujoco_warp/_src/io.py#L203)