[feat]: Create `<pf-v6-pagination>` element

[zeroedin]

Summary

Create `` to implement the PatternFly v6 Pagination component.

Page navigation controls for data views, with page/per-page controls and optional compact mode.

Prior Art

Source	Element	Status
PFE v4	--	--
cem	--	--
cockpit	--	--
chickadee	--	--
Red Hat	``	Exists

Requirements

• MUST implement PFv6 visual designs
• MUST provide end-user feature parity with `@patternfly/react-core` Pagination
• 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 `itemCount`, `page`, `perPage` - controlled props; map to `item-count`, `page`, `per-page` attributes
• React `onSetPage`, `onPerPageSelect`, `onFirstClick`, `onLastClick`, `onNextClick`, `onPreviousClick` - emit corresponding events (`page-change`, `per-page-change`, etc.)
• React `variant`: `top`, `bottom`, `left` - affects button arrangement; map to `variant` attribute
• React `isCompact` - compact layout; map to `compact` attribute
• React `isSticky` - CSS sticky positioning; map to `sticky` attribute
• React `isDisabled` - disables all controls
• React `perPageOptions` - array of `{ title, value }`; map to JSON attribute or `` sub-elements
• React `PaginationTitles` - i18n strings for button labels; map to `*-label` attributes
• First/last page buttons disabled at boundaries; prev/next disabled at start/end
• ARIA: each navigation button needs `aria-label`; page count is a live region if it updates

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`)