Square checkbox (no radius) with a hairline border that fills vermilion when checked. Pairs an inline sans label.

```jsx
<Checkbox
  checked={agreed}
  onChange={setAgreed}
  label="I agree to Plasma Orbital storing this information to respond to my enquiry."
/>
```

Controlled: `onChange` receives the next boolean. Use for consent rows and filters; keep the check square-cornered like everything else.
