# Description

This MR introduces the following:

* An `agent` argument to all scripts to allow selecting different entry
points (each then get resolved to their respective settings file).
* Symmetry function for ANYmal robot for the locomotion task and
cartpole balancing task
* Documentation on how to configure RL training agent using gym
resgistry

Fixes #2835

## Type of change

- New feature (non-breaking change which adds functionality)
- This change requires a documentation update

## Screenshots

### Cartpole

```bash
# without symmetry
./isaaclab.sh -p scripts/reinforcement_learning/rsl_rl/train.py --task Isaac-Cartpole-v0 --headless --agent rsl_rl_with_symmetry_cfg_entry_point --run_name ppo_with_no_symmetry agent.algorithm.symmetry_cfg.use_data_augmentation=false

# with symmetry
./isaaclab.sh -p scripts/reinforcement_learning/rsl_rl/train.py --task Isaac-Cartpole-v0--headless --agent rsl_rl_with_symmetry_cfg_entry_point --run_name ppo_with_symmetry_data_augmentation  agent.algorithm.symmetry_cfg.use_data_augmentation=true
```

| Isaac-Cartpole-v0 (pink w/o symmetry, blue w/ symmetry) |
| ------ |
| <img width="823" height="421" alt="image"
src="https://github.com/user-attachments/assets/9c33db99-0d79-4c1d-b437-e01275d613b5"
/> |

### Locomotion

```bash

# without symmetry
./isaaclab.sh -p scripts/reinforcement_learning/rsl_rl/train.py --task Isaac-Velocity-Rough-Anymal-D-v0 --headless --agent rsl_rl_with_symmetry_cfg_entry_point --run_name ppo_with_no_symmetry agent.algorithm.symmetry_cfg.use_data_augmentation=false

# with symmetry
./isaaclab.sh -p scripts/reinforcement_learning/rsl_rl/train.py --task Isaac-Velocity-Rough-Anymal-D-v0 --headless --agent rsl_rl_with_symmetry_cfg_entry_point --run_name ppo_with_symmetry_data_augmentation  agent.algorithm.symmetry_cfg.use_data_augmentation=true
```

| Isaac-Velocity-Rough-Anymal-D-v0 (green w/o symmetry, purple w/
symmetry) |
| ------ |
| <img width="1241" height="414" alt="image"
src="https://github.com/user-attachments/assets/625c125d-db9f-4006-9a62-0d55701a9407"
/> |

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

---------
Co-authored-by: Kelly Guo <kellyg@nvidia.com>
Co-authored-by: ooctipus <zhengyuz@nvidia.com>