Update Datapipes API

[coreyjadams]

PhysicsNeMo Pull Request

This PR updates the Datapipes API docs. The idea here was to break down the datapipes API into several pages that are smaller and more consumable. I separated the "legacy" datapipes (v1 format) and the composable datapipes (v2 format). The main intro page gives the high level summary and there are details on the subsequent pages.

Hard to review until it's rendered, but hard to render without the docs build ...

Description

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.
• The CHANGELOG.md is up to date with these changes.
• An issue is linked to this pull request.
• If I am implementing a new model or modifying any existing model, I have followed the Models Implementation Coding Standards.

Dependencies

Review Process

All PRs are reviewed by the PhysicsNeMo team before merging.

Depending on which files are changed, GitHub may automatically assign a maintainer for review.

We are also testing AI-based code review tools (e.g., Greptile), which may add automated comments with a confidence score.
This score reflects the AI’s assessment of merge readiness and is not a qualitative judgment of your work, nor is
it an indication that the PR will be accepted / rejected.

AI-generated feedback should be reviewed critically for usefulness.
You are not required to respond to every AI comment, but they are intended to help both authors and reviewers.
Please react to Greptile comments with 👍 or 👎 to provide feedback on their accuracy.

[greptile-apps]

Greptile Summary

Added comprehensive documentation for the PhysicsNeMo datapipes module, including new RST files for benchmarks, CAE, climate, GNN, readers, transforms, and the main datapipes page. The documentation includes usage examples, architecture diagrams, and API references.

Key changes:

• Reorganized datapipes documentation into dedicated subdirectory
• Added detailed docs for v2.0 redesigned datapipes architecture with GPU-first philosophy
• Documented legacy v1 datapipes for backward compatibility
• Included quick start guides and custom extension examples

Issues found:

• Multiple spelling errors in main documentation files that need correction
• Missing newline at end of one file

Important Files Changed

Filename	Overview
docs/api/datapipes/physicsnemo.datapipes.cae.rst	added CAE datapipes docs; has typo on line 18 and missing newline at EOF
docs/api/datapipes/physicsnemo.datapipes.rst	added main datapipes documentation; contains multiple typos (lines 14, 35, 49, 156, 159)
docs/api/datapipes/physicsnemo.datapipes.transforms.rst	added transforms documentation; has typo on line 25

_{Last reviewed commit: 0897f6d}

[greptile-apps]

_{8 files reviewed, 8 comments}

_{Edit Code Review Agent Settings | Greptile}

[ktangsali]

Looks good, have a few minor comments.