[feat]: Update `<pf-v6-hint>` for PatternFly v6

[bennypowers]

Summary

Update `` to implement the PatternFly v6 Hint component.

Contextual hint block with title, body, and optional footer actions, used inline within page content.

Prior Art

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

Requirements

• MUST implement PFv6 visual designs
• MUST provide end-user feature parity with `@patternfly/react-core` Hint
• 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 sub-components: `HintTitle`, `HintBody`, `HintFooter` - use named slots: `slot="title"`, `slot="footer"`; default slot for body
• React `HintTitle` has `headingLevel` prop (`h1`-`h6`) and `hasTitle` (icon variant) - consider `heading-level` attribute or slotted heading element
• No interactive behavior; purely presentational block
• Verify if v6 changed the sub-component structure vs v5

Checklist

Rename

• Delete `elements/pf-v5-hint/`
• Update `elements/package.json` exports
• Update `eslint.config.js` ignore globs if applicable
• Update docs `_snippets/` and `framework-integration/` references

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`)