[feat]: Create <pf-v6-simple-list> element #3035

Summary

Create `` to implement the PatternFly v6 Simple list component.

Actionable list of selectable items, simpler alternative to a data list or table for flat lists.

Prior Art

Sub-components

• `` - Individual selectable item
• `` - Grouped items with title

Requirements

• MUST implement PFv6 visual designs
• MUST provide end-user feature parity with `@patternfly/react-core` SimpleList
• MAY adjust element API to leverage web platform strengths
• SHOULD maintain CSS custom property theming compatibility
• SHOULD expose useful CSS shadow parts

Element-specific considerations

• React `isControlled` - whether selection state is managed externally
• `SimpleListItem` props: `isCurrent` (selected), `onClick`, `component` (`button` or `a`), `href`, `target`
• `SimpleListGroup` has a `titleId` and `title` - renders as `
• ` with `
  ` inside
  • Emit `select` event from items with the selected item reference
  • ARIA: `role="list"` on container; items are buttons/links (no special ARIA needed beyond standard button/link roles)
  • Selected item: `aria-current="true"` or just visual styling (verify React behavior)

  Checklist

  Implementation

  • API per `.claude/ADVICE.md`
  • CSS uses v6 tokens, logical properties, nesting
  • `@summary` and JSDoc on element class

  Demos

  • Demos match patternfly.org naming/structure
  • CSS custom properties match computed styles from patternfly.org (Chrome MCP)
  • Visual parity verified via Chrome MCP

  Tests

  • Public API covered (attributes, properties, events, slots)
  • `a11ySnapshot` assertions

  Reviews

  • `/review-api` passes
  • `/review-demos` passes
  • `/review-a11y` passes
  • `eslint` and `stylelint` pass

  Ship

  • Add changeset
  • PR targets `staging/pfv6` (NOT `main`)