Add RadioButtonField and RadioGroupField for CommandForm

[Copilot]

Adds PrimeReact-based radio button support to the CommandForm field set, matching the pattern established by existing fields.

Added

• RadioButtonField: single PrimeReact RadioButton bound to a specific buttonValue; multiple instances on the same command property form a natural radio group (#issue)
• RadioGroupField: renders a full radio button group from an options array with optionLabel/optionValue props (mirrors DropdownField API); supports 'vertical' (default) and 'horizontal' layouts (#issue)
• Storybook stories for both fields, including entries in the AllFields showcase (#issue)
• Documentation pages for RadioButtonField and RadioGroupField with props tables and usage examples (#issue)

// Single buttons sharing a property form a group
<RadioButtonField<MyCommand> value={c => c.size} buttonValue="small" label="Small" />
<RadioButtonField<MyCommand> value={c => c.size} buttonValue="large" label="Large" />

// Or use RadioGroupField with an options array
<RadioGroupField<MyCommand>
    value={c => c.size}
    options={sizeOptions}
    optionLabel="label"
    optionValue="id"
    layout="horizontal"
/>