Polish Feynman harness and stabilize Pi web runtime

src/setup/prompts.ts

@@ -0,0 +1,30 @@
+import { stdin as input, stdout as output } from "node:process";
+import { createInterface } from "node:readline/promises";
+
+export async function promptText(question: string, defaultValue = ""): Promise<string> {
+	if (!input.isTTY || !output.isTTY) {
+		throw new Error("feynman setup requires an interactive terminal.");
+	}
+	const rl = createInterface({ input, output });
+	try {
+		const suffix = defaultValue ? ` [${defaultValue}]` : "";
+		const value = (await rl.question(`${question}${suffix}: `)).trim();
+		return value || defaultValue;
+	} finally {
+		rl.close();
+	}
+}
+
+export async function promptChoice(question: string, choices: string[], defaultIndex = 0): Promise<number> {
+	console.log(question);
+	for (const [index, choice] of choices.entries()) {
+		const marker = index === defaultIndex ? "*" : " ";
+		console.log(`  ${marker} ${index + 1}. ${choice}`);
+	}
+	const answer = await promptText("Select", String(defaultIndex + 1));
+	const parsed = Number(answer);
+	if (!Number.isFinite(parsed) || parsed < 1 || parsed > choices.length) {
+		return defaultIndex;
+	}
+	return parsed - 1;
+}