fix(frontend): expose focus method on FormField component

Components using FormField with a ref need to call .focus() on it.
Without exposing the method, these calls would fail since the ref
points to the component instance, not the underlying input element.

frontend/src/components/input/FormField.vue

@@ -59,6 +59,9 @@ defineExpose({
 	get value() {
 		return inputRef.value?.value ?? ''
 	},
+	focus() {
+		inputRef.value?.focus()
+	},
 })
 </script>