Refactor tool confirmation radio buttons to own component.

- I plan to utilize these radio buttons for theme selection in the future. Refactoring them into their own component.

Part of https://b.corp.google.com/issues/412797985

packages/cli/src/ui/components/shared/RadioButtonSelect.tsx

@@ -0,0 +1,90 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import React from 'react';
+import { Box, Text } from 'ink';
+import SelectInput, {
+  type ItemProps as InkSelectItemProps,
+  type IndicatorProps as InkSelectIndicatorProps,
+} from 'ink-select-input';
+import { Colors } from '../../colors.js';
+
+/**
+ * Represents a single option for the RadioButtonSelect.
+ * Requires a label for display and a value to be returned on selection.
+ */
+export interface RadioSelectItem<T> {
+  label: string;
+  value: T;
+}
+
+/**
+ * Props for the RadioButtonSelect component.
+ * @template T The type of the value associated with each radio item.
+ */
+export interface RadioButtonSelectProps<T> {
+  /** An array of items to display as radio options. */
+  items: Array<RadioSelectItem<T>>;
+
+  /** The initial index selected */
+  initialIndex?: number;
+
+  /** Function called when an item is selected. Receives the `value` of the selected item. */
+  onSelect: (value: T) => void;
+}
+
+/**
+ * Custom indicator component displaying radio button style (◉/○).
+ */
+function RadioIndicator({
+  isSelected = false,
+}: InkSelectIndicatorProps): React.JSX.Element {
+  return (
+    <Box marginRight={1}>
+      <Text color={isSelected ? Colors.AccentGreen : Colors.Gray}>
+        {isSelected ? '◉' : '○'}
+      </Text>
+    </Box>
+  );
+}
+
+/**
+ * Custom item component for displaying the label with appropriate color.
+ */
+function RadioItem({
+  isSelected = false,
+  label,
+}: InkSelectItemProps): React.JSX.Element {
+  return (
+    <Text color={isSelected ? Colors.AccentGreen : Colors.Gray}>{label}</Text>
+  );
+}
+
+/**
+ * A specialized SelectInput component styled to look like radio buttons.
+ * It uses '◉' for selected and '○' for unselected items.
+ *
+ * @template T The type of the value associated with each radio item.
+ */
+export function RadioButtonSelect<T>({
+  items,
+  initialIndex,
+  onSelect,
+}: RadioButtonSelectProps<T>): React.JSX.Element {
+  const handleSelect = (item: RadioSelectItem<T>) => {
+    onSelect(item.value);
+  };
+  initialIndex = initialIndex ?? 0;
+  return (
+    <SelectInput
+      indicatorComponent={RadioIndicator}
+      itemComponent={RadioItem}
+      items={items}
+      initialIndex={initialIndex}
+      onSelect={handleSelect}
+    />
+  );
+}