Use this skill whenever configuring lesson frontmatter or checking inheritance rules.
Trigger on: 'frontmatter', 'prepareCommands', 'mainCommand', 'editor config', 'terminal
config', 'preview config', 'configuration inheritance', 'focus file', 'i18n', 'allowEdits',
'previews', 'autoReload', 'scope', 'defaults', 'what inherits', 'does X inherit',
'invalid combination', 'constraint', or any YAML frontmatter question — even without
mentioning configuration. Authoritative reference for all frontmatter options, inheritance
rules, defaults, and invalid-combination constraints with Rails-specific patterns. Do NOT
guess frontmatter without this skill. Do NOT use for content hierarchy
(use tutorial-content-structure) or file organization (use rails-file-management).