Maintain Vue markup linting specs

Add Vue global attributes and element-specific overrides

Maintaining Vue markup spec in markuplint by adding custom global attributes and element overrides without modifying parsing logic.

• · Task type: 'add-global-attribute' or 'add-element-override'
• · Attribute name, type, description
• · CSS selector condition (optional)

• · Extended Vue spec definition in src/index.ts
• · Build artifact via yarn build --scope @markuplint/vue-spec
• · Test results via yarn test --scope @markuplint/vue-spec

• · yarn (build tool)
• · @markuplint/ml-spec (for ExtendedSpec type reference)

• · Read docs/maintenance.md for procedure
• · Understand ExtendedSpec structure from ARCHITECTURE.md
• · Yarn development environment configured

• · Build fails if invalid type or missing required fields
• · Tests fail if attribute doesn't integrate with ml-spec
• · Conditional attributes fail if CSS selector is malformed

• · Template steps reference source-of-truth docs
• · Build and test commands provided for verification
• · Rules explicitly prevent parsing logic in package scope