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

Start by reading .claude/ADVICE.md and the existing pf-v6-select component as the model for API, floating UI, and styling patterns. Review the PatternFly v6 Time picker design and the listed accessibility, form, demo, and review requirements. Done means the component, demos, public API tests, accessibility snapshots, form submission behavior, changeset, and required checks are complete for staging/pfv6.

Summary

Create a <pf-v6-time-picker> web component implementing the PatternFly v6 Time picker component.

Time selection input with dropdown suggestions for 12-hour and 24-hour formats.

Prior Art

Requirements

• MUST implement PFv6 visual designs
• MUST provide end-user feature parity with @patternfly/react-core TimePicker
• 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

• FACE: formAssociated = true, ElementInternals - submits time string value
• time / value prop (string, e.g. "2:00 AM" or "14:00")
• is24Hour prop for format toggle
• stepMinutes for dropdown suggestion interval (default 30)
• minTime / maxTime to restrict valid range
• placeholder for input hint text
• Text input with typed entry + time suggestions dropdown (combobox pattern)
• Combobox: role="combobox", aria-expanded, aria-controls pointing to listbox
• Listbox: role="listbox", options role="option", aria-selected
• Floating UI for dropdown positioning (consider pf-v6-select as model)
• Validation: parse typed time, check against min/max, set aria-invalid
• Keyboard: Arrow down opens suggestions, Arrow up/down navigates, Enter selects, Escape closes

Checklist

Implementation

• formAssociated = true
• ElementInternals for value/validity reporting
• 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
• Form submission test

Reviews

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

Ship

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