docs: add datashuttle demo GIF to documentation homepage

[Sushma-1706]

Description

What is this PR
Other (documentation improvement)

Why is this PR needed?
The documentation landing page currently contains only static images.
Adding a lightweight demo GIF gives new users a quick visual overview of how
datashuttle works, helping them understand the tool without reading through
multiple pages.

This was suggested in issue #577.

What does this PR do?
This PR adds a demo GIF to the documentation homepage using Sphinx’s
{image} directive.
The GIF is stored in the _static directory and displayed prominently on the
landing page without replacing the existing light and dark images.

References
Closes #577

How has this PR been tested?
This change is documentation-only.
The documentation was built locally to confirm that the GIF renders correctly
and does not affect layout or styling.

Is this a breaking change?
No. This PR does not change any runtime behavior or APIs.

Does this PR require an update to the documentation?
Yes. This PR updates the documentation homepage by adding a demo GIF.

Checklist
Documentation has been updated to reflect the change
No code or behavior changes were introduced

[JoeZiminski]

Hi @Sushma-1706 thanks for this, I see this PR includes the commit related to the developer documentation. This is a common problem with git, when you make a new branch if you do not branch off main but instead branch off a PR branch, you will include those commits. Because you are on a fork make sure to sync for your fork main with the datashuttle main using the button on the GitHub interface

The easiest way to deal with this is to git rebase onto main and drop the extra commits. You can follow this guide. The main workflow will be to

git commit main
git pull
git checkout docs-add-gif
git rebase -i main

and then follow that guide to drop the old commit

[Sushma-1706]

Thanks for the clarification @JoeZiminski — that makes sense 👍 Sorry about that, I’ll rebase the branch onto `main` and drop the extra commit now.

…

On Fri, Jan 2, 2026 at 8:12 PM Joe Ziminski ***@***.***> wrote: *JoeZiminski* left a comment (neuroinformatics-unit/datashuttle#660) <#660 (comment)> Hi @Sushma-1706 <https://github.com/Sushma-1706> thanks for this, I see this PR includes the commit related to the developer documentation. This is a common problem with git, when you make a new branch if you do not branch off main but instead branch off a PR branch, you will include those commits. The easiest way to deal with this is to git rebase onto main and drop the extra commits. You can follow this guide <https://alchemists.io/articles/git_rebase_drop>. The main workflow will be to git commit main git pull git checkout Sushma-1706:docs-add-gif git rebase -i main and then follow that guide to drop the old commit — Reply to this email directly, view it on GitHub <#660 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BMV5AMLUFTWNAHOMAT6P3UT4EZ7U7AVCNFSM6AAAAACPYCJAHCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTOMBVGUYDCNJYGE> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[Sushma-1706]

Thanks for the review and guidance @JoeZiminski 🙏
I’ve rebased the branch onto main, dropped the unrelated commit, and force-pushed the cleaned history.
All checks are now passing. Please let me know if you’d like any further changes.

[JoeZiminski]

Brilliant, thanks @Sushma-1706! I've approved the workflow runs, you will see on the 'Checks' tab there is an 'artifact.ci' section. This contains a preview of the docs on any PR. I'll test this on a new PCs / networks to double check and get back to you, but in general this looks great. thanks!