Replace Naive UI checkbox, radio, and switch controls

[nighca]

Background

As part of #3017, another sub-area is boolean / choice controls.

Current dependency points include:

• src/components/ui/UISwitch.vue
• src/components/ui/checkbox/UICheckbox.vue
• src/components/ui/checkbox/UICheckboxGroup.vue
• src/components/ui/radio/UIRadio.vue
• src/components/ui/radio/UIRadioGroup.vue

Problem

These controls are currently still thin wrappers over naive-ui:

• UISwitch wraps NSwitch
• UICheckbox / UICheckboxGroup wrap NCheckbox / NCheckboxGroup
• UIRadio / UIRadioGroup wrap NRadio / NRadioGroup

Individually these wrappers are small, but together they keep naive-ui in the dependency graph and make our control layer incomplete.

Goal

Replace the remaining naive-ui choice controls with internal implementations that match the current UI* APIs used across the app.

Scope

• replace NSwitch
• replace NCheckbox / NCheckboxGroup
• replace NRadio / NRadioGroup
• preserve checked/value update behavior, disabled states, grouping semantics, and current slot/content usage
• ensure these controls continue to work correctly within the XBuilder form layer after the form infrastructure migration

Notes

This issue is about boolean / discrete choice controls only. Form infrastructure and text/numeric inputs are tracked separately.