First pass at pulling the v1.5 CLI, TUI, and Launcher clients into v2.

clients/tui/src/components/SelectableItem.tsx

@@ -0,0 +1,22 @@
+import React from "react";
+import { Box, Text } from "ink";
+
+/** Renders a selectable item: ▶ + space when selected, space + space when not. Fixed width to prevent layout shift. */
+export function SelectableItem({
+  isSelected,
+  bold,
+  children,
+}: {
+  isSelected: boolean;
+  bold?: boolean;
+  children: React.ReactNode;
+}) {
+  return (
+    <Box flexShrink={0} flexDirection="row">
+      <Box width={2}>
+        <Text bold={bold}>{isSelected ? "▶ " : "  "}</Text>
+      </Box>
+      <Text bold={bold}>{children}</Text>
+    </Box>
+  );
+}