docs: add release notes for 0.4.0

[gabwow]

Summary

Create release notes for 0.4.0 based on the POR and what has actually been merged into mainline since 0.3.0.

I ignored eval-author since it's mostly scaffolding.

Changes

• moved latest to 0.3.0
• added release notes for 0.4.0

Type of Change

• Code change (feature, bug fix, or refactor)
• Code change with documentation updates
• Documentation only
• Contributor tooling or automation
• CI, build, or test infrastructure

Quality Gates

• Tests added or updated for changed behavior
• Existing tests cover changed behavior — justification:
• Tests not applicable — justification:
• Documentation updated for user-visible behavior
• Documentation not applicable — justification:

Verification

• Pull request title follows the repository's Conventional Commit format
• Every commit includes an appropriate Signed-off-by: trailer
• uv run pre-commit run -a passes, or any blocked checks are identified below
• Targeted tests pass, or tests are marked not applicable above
• No secrets, API keys, or credentials are included

Targeted validation:

Summary by CodeRabbit

• Documentation
  • Updated the current release notes for v0.4.0 with information about agent optimization, telemetry, evaluators, Customizer DPO, Studio, deployment, CLI improvements, Python support, and NeMo Fabric.
  • Added updated upgrade guidance, compatibility details, and platform constraints.
  • Added a dedicated v0.3.0 release notes page covering deployment, installation, supported environments, capabilities, and limitations.
  • Updated release note navigation and links for easier access.

[github-actions]

🌿 Preview your docs: https://nvidia-preview-pr-1194-agabow-release-notes-0-4-0.docs.buildwithfern.com/nemo-platform

[coderabbitai]

📝 Walkthrough

Walkthrough

The release documentation now covers v0.4.0, moves v0.3.0 to a dedicated page, and updates the release-note index and documentation navigation.

Changes

Release notes versioning

Layer / File(s)	Summary
v0.4.0 release content docs/about/release-notes/current-release.mdx	Documents v0.4.0 features, compatibility requirements, constraints, upgrade guidance, and NeMo Fabric links.
v0.3.0 release archive docs/about/release-notes/release-0-3-0.mdx	Adds dedicated v0.3.0 notes with installation, upgrade, compatibility, limitations, and project links.
Release navigation wiring docs/about/release-notes/index.mdx, docs/fern/versions/latest.yml	Links the v0.4.0 and v0.3.0 release pages and adds v0.3.0 to documentation navigation.

Possibly related PRs

• NVIDIA-NeMo/nemo-platform#781: Updates Python-version compatibility in release notes.
• NVIDIA-NeMo/nemo-platform#787: Updates release-note pages and navigation for another platform version.
• NVIDIA-NeMo/nemo-platform#1171: Updates the same v0.4.0, v0.3.0, and navigation pages.

Suggested reviewers: anastasia-nesterenko, benmccown, tylersbray

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the addition of the 0.4.0 release notes.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch agabow/release-notes-0.4.0

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_{Comment @coderabbitai help to get the list of available commands.}

[github-actions]

Suite	Lines Covered	Line Rate	Branch Rate
Unit Tests	31725/40339	78.6%	63.3%
Integration Tests	18444/38269	48.2%	20.9%