docs(ngc-managed): fix broken links in cluster-management docs

[mesutoezdil]

Related Documentation links in reference.md and kai-scheduler.md used slugs that match no real file. Pointed them at the real configuration.md and helm-managed.md files/sections.

Tested: verified each target exists, ran ./tools/ci/check-docs (0 errors).

Refs: NO-REF

[coderabbitai]

📝 Walkthrough

Walkthrough

Updated cluster management documentation links for KAI Scheduler feature flags, configuration, Helm-managed clusters, and agent configuration merging.

Changes

Cluster management documentation

Layer / File(s)	Summary
Update cluster management documentation links docs/ngc-managed/cluster-management/kai-scheduler.md, docs/ngc-managed/cluster-management/reference.md	Updated links to use current relative paths and configuration anchors, including feature flags, Helm-managed clusters, and agent config merging.

Estimated code review effort: 1 (Trivial) | ~2 minutes

🚥 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 accurately summarizes the main change: fixing broken links in cluster-management documentation.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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

[pdmack]

This PR is one of four that together fix the lychee link check failures currently blocking CI on other PRs (e.g. #252). Verified locally: with #240, #241, #242, and #261 all applied, lychee --offline and fern check both pass with zero errors.

Note: broader broken-link issues remain visible via fern check --broken-links (14 additional errors in nav-tree resolution, pre-existing and out of scope here).

@sbaum1994 -- can you review and approve so these can merge?