feat: add keyboard navigation and ARIA support to font picker

Keyboard Shortcuts

When the font picker is focused:

• Enter/Space: Open the dropdown
• Escape: Close the dropdown
• Tab: Navigate to next/previous focusable element

When the dropdown is open:

• Arrow Up/Down: Navigate through font options
• Enter/Space: Select the highlighted font
• Home: Jump to first font option
• End: Jump to last font option
• Escape: Close dropdown and return focus to trigger
• Tab: Close dropdown and move to next focusable element

feat: add category filtering and preselection support to font picker

New methods

• Available Categories: Restrict which font categories are displayed.
• Selected Categories: Specify categories preselected on load.

Full Changelog: 1.0.0...1.1.0