c08e1d9e6e
This change introduces two new USD API schema: * MjcEqualityAPI - base API for representing MuJoCo equality constraints in USD, this will typically be applied to joints such as UsdPhysicsFixedJoint. * MjcEqualityWeldAPI - extends MjcEqualityAPI for MuJoCo's weld equality constraints with an attribute for torqueScale. The usd_decoder is updated to parse UsdPhysicsFixedJoints and convert the new schema attributes into the appropriate mjsEquality data fields. PiperOrigin-RevId: 856723634 Change-Id: I0982fd3168b643f8e91d87bb5ae5933e526b63a1