[Feature] Create `lightspeed-label-governance` skill

[ashleyshaw]

Summary

Create a P0 skill for reviewing labels, issue templates, saved replies, and triage conventions across LightSpeed repositories.

Parent epic: #283.

Proposed Solution

Add /skills/lightspeed-label-governance/SKILL.md with governance checks, expected inputs, findings format, and remediation guidance.

Acceptance Criteria

• Skill folder exists with SKILL.md.
• Skill name matches folder name.
• Skill covers labels, issue types, templates, saved replies, and triage conventions.
• Skill references canonical .github files without moving them.
• Skill is eligible for inclusion in plugins/lightspeed-github-ops.
• Documentation/changelog updated.
• PR uses correct branch prefix feat/.

[linear-code]

LS-618

[ashleyshaw]

Completed on 2026-05-26. Added skills/lightspeed-label-governance/SKILL.md with read-only governance checks. Validation: npm run validate:skills (pass).