[Task] Document current-state project-meta-sync contract #506

Deliverable

Document current project-meta-sync behaviour as-is, including preflight requirements and Status/Priority/Type field sync boundaries.

Scope Boundary

• In scope: documentation of current behaviour.
• Out of scope: extending synced fields or workflow refactors.

Acceptance Checklist

• Preflight requirements are documented (LS_PROJECT_URL, LS_APP_ID, LS_APP_PRIVATE_KEY).
• Synced fields explicitly limited to Status, Priority, Type.
• Close/merge status handling and defaults are documented.
• References point to canonical workflow and field mapping YAML.

Branch Prefix Expectation

• Use docs/.

Validation Commands

npx markdownlint-cli2 "docs/ISSUE-FIELDS.md" "docs/GITHUB_PROJECT_OPERATIONS_SPEC.md"
node scripts/validation/validate-issue-fields.cjs

Touched Paths

• docs/ISSUE-FIELDS.md
• docs/GITHUB_PROJECT_OPERATIONS_SPEC.md
• .github/workflows/project-meta-sync.yml
• .github/issue-fields.yml