fix: make rh-ai-engineer skills fully self-contained (pipeline-manage, serving-runtime-config)

[dmartinol]

Summary

PR #141 fixed upward traversal links (../references/) in 9 of the 11 rh-ai-engineer skills. Two skills were missed and still reference files outside their own folder:

rh-ai-engineer/skills/pipeline-manage/SKILL.md

• ../references/skill-conventions.md
• ../references/openshift-fallback-templates.md
• ../references/common-issues.md

rh-ai-engineer/skills/serving-runtime-config/SKILL.md

• ../references/skill-conventions.md
• ../references/openshift-fallback-templates.md
• ../references/live-doc-lookup.md

Fix

Apply the same treatment used for the other 9 skills:

1. Create a references/ subdirectory in each skill folder
2. Add symlinks pointing to ../../references/[file] for each referenced file
3. Update all ../references/ markdown links to references/ (local)

Notes

rh-ai-engineer is not yet a mature pack, so this can be postponed. Tracked separately from #141 to keep the fix targeted.