Fix broken links: vendor references/config.md for skill.md - #320

Summary

Maintenance fixes found by mint broken-links and mint validate: a broken relative link in skill.md and an MDX parse error in performance/checkpointing.mdx.

Changes

• Broken link: skill.md (line 45) links to references/config.md with a relative path. The file exists upstream in CerebriumAI/cerebrium-skills but not here, so the link resolved to a non-existent page.
  • Fix: vendored skills/cerebrium/references/config.md from CerebriumAI/cerebrium-skills into references/config.md. The relative link now resolves. skill.md itself is untouched, since the upstream sameness check requires it to stay byte-identical.
  • Added /references/config.md to .prettierignore with a note explaining it is vendored, matching the existing skill.md exemption.
• Parse error: docs: explain why a checkpoint failed and how to fix it #335 added an HTML comment (<!-- ... -->) to performance/checkpointing.mdx, which MDX cannot parse, so mint validate and mint broken-links failed on the page.
  • Fix: converted it to MDX comment syntax ({/* ... */}), preserving the comment text. Verified the four agent-linked anchors (#vllm-uses-fork-by-default, #open-gpu-file-descriptors, #cuda-unified-memory, #unknown-cause) still resolve.

Context

Triggered by the merges of #318 (vendored skill.md) and #335 (checkpoint failure docs). mint validate and mint broken-links both pass.