add DurationInput component

src/lib/index.ts

@@ -6,6 +6,12 @@ export { default as Checkbox, type CheckboxState } from './Checkbox.svelte';
 export { default as Combobox, type ComboboxOption } from './Combobox.svelte';
 export { default as DateInput } from './DateInput.svelte';
 export { default as Dialog, type DialogAPI, type DialogControlOpts } from './Dialog.svelte';
+export {
+	default as DurationInput,
+	formatDuration,
+	durationToISO8601,
+	iso8601ToDuration
+} from './DurationInput.svelte';
 export { default as ErrorBox } from './ErrorBox.svelte';
 export { default as FramelessButton } from './FramelessButton.svelte';
 export { default as InjectGoogleMaps } from './InjectGoogleMaps.svelte';