[RFC] Introducing transform primatives for sim2real #4422

##Summary:

• Six transforms for sim-to-real + Compose recipes over existing mechanics.
• DomainRandomization needs a small protocol on EnvBase.
• these are the primatives i think we need to introduce:
  ObservationDelay, ActionDelay,
  ObservationNoise, ActuatorModel, SymmetryAugmentation, DomainRandomization.
  DomainRandomization
  ##RFC decision for domainrandomization interaction with sim
  • A. EnvBase.physics_param_spec + set_physics_params(td); transform samples in _reset.
  • B. Config field on MujocoEnvBase. Not composable, not loggable, no Isaac Lab path.
  • C. Transform mutates env.unwrapped directly. No spec, breaks under ParallelEnv.