feat: TypeScript installation wizard with @clack/prompts TUI (#1)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

src/runtime/installer.ts

@@ -0,0 +1,12 @@
+import type { RuntimeName } from '../types.js';
+import { getInstallInstructions } from './detector.js';
+
+export function formatInstallInstructions(name: RuntimeName): string {
+  const hint = getInstallInstructions(name);
+  const labels: Record<RuntimeName, string> = {
+    claude: 'Claude Code',
+    codex: 'Codex',
+    opencode: 'OpenCode',
+  };
+  return `To install ${labels[name]}:\n  ${hint}`;
+}