# Description

<!--
Thank you for your interest in sending a pull request. Please make sure
to check the contribution guidelines.

Link: https://isaac-sim.github.io/IsaacLab/source/refs/contributing.html
-->

This PR adds observation history by adding configuration parameters to
ObservationTerms and having the ObservationManager handling the
collection and storage of the histories via CircularBuffers.

Fixes #1208 

<!-- As a practice, it is recommended to open an issue to have
discussions on the proposed pull request.
This makes it easier for the community to keep track of what is being
developed or added, and if a given feature
is demanded by more than one party. -->

## Type of change

<!-- As you go through the list, delete the ones that are not
applicable. -->

- New feature (non-breaking change which adds functionality)

## 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
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] 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

<!--
As you go through the checklist above, you can mark something as done by
putting an x character in it

For example,
- [x] I have done this task
- [ ] I have not done this task
-->

---------
Signed-off-by: Kelly Guo <kellyg@nvidia.com>
Co-authored-by: Fangzhou Yu <156015326+fyu-bdai@users.noreply.github.com>
Co-authored-by: Kelly Guo <kellyg@nvidia.com>