docs: Add initial fern migration

[chtruong814]

What does this PR do ?

docs: Add initial fern migration

• Migrated nightly docs. We can re-render this when we want to switch over
• Migrated 0.4.2 docs. We can migrate more and backfill if we want. Just did this to show example
• Include the docs team recommended github actions for fern
• With fern, all versions of docs are on same branch. This is a known issue that docs team has raised to see if we can resolve

Used docs team's fern migrate skill to do this. Had to resolve a few issues with agent like ensuring rendering of github badges were horizontal.

The docs team will enable a staging site for us to evaluate before we choose to cut over

To render locally

npm install -g fern-api
cd docs/fern && npx fern-api docs dev

Changelog

• Add specific line by line info of high level changes in this PR.

GitHub Actions CI

See the CI section in the Contributing doc for how to trigger the CI. A Nvidia developer will need to approve and trigger the CI for external contributors.

Before your PR is "Ready for review"

Pre checks:

• Make sure you read and followed Contributor guidelines
• Did you write any new necessary tests?
• Did you add or update any necessary documentation?
• Does the PR affect components that are optional to install? (Ex: Numba, Pynini, Apex etc)
  • Reviewer: Does the PR have correct import guards for all optional libraries?

If you haven't finished some of the above items you can still open "Draft" PR.

Additional Information

• Related to # (issue)

[claude]

Bug: React.ReactNode is used here without importing React. Other components in this PR explicitly avoid importing React because "the react module is not resolvable in Fern's build." This will cause a build error.

Suggested change

	children: React.ReactNode;
	children: import("react").ReactNode;

Alternatively, match the pattern in NotebookViewer.tsx and use a type-only import:

import type { ReactNode } from "react";

then use children: ReactNode.

[claude]

Bug: This imports from "./devnotes/authors-data" but no devnotes/ directory exists under docs/fern/components/ in this PR. If this component is rendered, it will fail at build time with a module-not-found error. Either add the missing authors-data module to this PR, or guard the import so the component degrades gracefully when the module is absent.

[claude]

Bug: This is pinned to actions/checkout v4.2.2, while the repo convention (and the other three new workflows in this PR) uses @v6. This should be updated for consistency and to get the latest features/fixes.

Suggested change

	uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
	uses: actions/checkout@v6

[claude]

Nit: This file uses LicenseRef-NvidiaProprietary while all other new components in this PR use Apache-2.0. Is this intentional? The rest of the repo is Apache-2.0 licensed.

[claude]

Code Review: 1) Bug - Tag.tsx uses React.ReactNode without importing React (Tag.tsx:41), will cause build error. 2) Bug - Authors.tsx imports missing devnotes/authors-data module (Authors.tsx:23). 3) Bug - fern-docs-preview-build.yml pins actions/checkout to v4.2.2, repo convention is v6. 4) License mismatch - CustomFooter.tsx uses LicenseRef-NvidiaProprietary, other components use Apache-2.0. 5) Duplicate nav titles in 0.4.2.yml (lines 13-15), two entries both titled Performance. Suggested test cases: No perf tests impacted.