refactor: improve menu with shared helpers and error boundaries

- Use shared terminal helpers (hideCursor, showCursor, clearLine,
  moveUp, visibleLength, padRight) from terminal.ts
- Fix normalizeKey to properly buffer SS3 escape sequences (\x1bO)
- Add try/catch+cleanup error boundaries in selectOne and selectMany
  to prevent terminal state leaks (raw mode, hidden cursor) on errors

Co-Authored-By: Claude <noreply@anthropic.com>

src/menu.ts

@@ -1,4 +1,4 @@
-import { BOLD, GREEN, CYAN, DIM, RESET } from "./terminal";
+import { BOLD, GREEN, CYAN, DIM, RESET, hideCursor, showCursor, clearLine, moveUp, visibleLength, padRight } from "./terminal";
 import { isStdinTTY } from "./tty";
 
 const UP = "\x1b[A";
@@ -43,22 +43,7 @@ interface MultiPromptOptions<T> extends BasePromptOptions {
   doneLabel?: string;
 }
 
-function hideCursor() { process.stdout.write("\x1b[?25l"); }
-function showCursor() { process.stdout.write("\x1b[?25h"); }
-
-function moveUp(lines: number) {
-  if (lines > 0) process.stdout.write(`\x1b[${lines}A`);
-}
-
-function clearLine() {
-  process.stdout.write("\r\x1b[2K");
-}
-
-function visibleLength(value: string) {
-  return value.replace(/\x1b\[[0-9;]*m/g, "").length;
-}
-
-function padLabel(label: string, width: number) {
+function padLabel(label: string, width: number): string {
   return label + " ".repeat(Math.max(1, width - visibleLength(label)));
 }
 
@@ -92,7 +77,8 @@ function clearPrompt(lines: number) {
   moveUp(lines);
 }
 
-function normalizeKey(key: string, escapeBuf: string) {
+function normalizeKey(key: string, escapeBuf: string): { action: string | null; escapeBuf: string } {
+  // Single-chunk actions
   if (key === UP || key === ALT_UP) return { action: "up", escapeBuf: "" };
   if (key === DOWN || key === ALT_DOWN) return { action: "down", escapeBuf: "" };
   if (key === LEFT || key === ALT_LEFT || key === BACKSPACE) return { action: "back", escapeBuf: "" };
@@ -100,14 +86,20 @@ function normalizeKey(key: string, escapeBuf: string) {
   if (key === ENTER) return { action: "enter", escapeBuf: "" };
   if (key === CTRL_C) return { action: "cancel", escapeBuf: "" };
 
-  if (key === "\x1b" || key.startsWith("\x1b[")) return { action: null, escapeBuf: key };
+  // Start of an escape sequence — buffer it
+  if (key === "\x1b" || key.startsWith("\x1b[") || key.startsWith("\x1bO")) {
+    return { action: null, escapeBuf: key };
+  }
 
+  // Continue buffering an escape sequence
   if (escapeBuf) {
     const next = escapeBuf + key;
     if (next === UP || next === ALT_UP) return { action: "up", escapeBuf: "" };
     if (next === DOWN || next === ALT_DOWN) return { action: "down", escapeBuf: "" };
     if (next === LEFT || next === ALT_LEFT) return { action: "back", escapeBuf: "" };
-    return { action: null, escapeBuf: /^[A-Za-z~]$/.test(key) || next.length > 8 ? "" : next };
+    // If key is a terminal character (letter/digit/~) or buffer got too long, flush
+    if (/^[A-Za-z~0-9]$/.test(key) || next.length > 10) return { action: null, escapeBuf: "" };
+    return { action: null, escapeBuf: next };
   }
 
   return { action: null, escapeBuf: "" };
@@ -168,15 +160,25 @@ export async function selectOne<T>(
   const render = () => {
     renderedLines = renderPrompt(createLines(options, "single", cursor), renderedLines);
   };
-  render();
 
-  return new Promise((resolve) => {
-    const finish = (value: T | null | PromptBack) => {
+  const cleanup = () => {
     process.stdin.setRawMode(wasRaw === true);
     process.stdin.pause();
-      process.stdin.removeListener("data", onData);
     clearPrompt(renderedLines);
     showCursor();
+  };
+
+  try {
+    render();
+  } catch (err) {
+    cleanup();
+    throw err;
+  }
+
+  return new Promise((resolve, reject) => {
+    const finish = (value: T | null | PromptBack) => {
+      process.stdin.removeListener("data", onData);
+      cleanup();
       if (value === null && options.cancelMessage) {
         process.stdout.write(`  ${options.cancelMessage}\n`);
       }
@@ -184,6 +186,7 @@ export async function selectOne<T>(
     };
 
     const onData = (data: Buffer) => {
+      try {
         const result = normalizeKey(data.toString(), escapeBuf);
         escapeBuf = result.escapeBuf;
 
@@ -194,6 +197,10 @@ export async function selectOne<T>(
         else if (result.action === "space" || result.action === "enter") {
           finish(options.items[cursor]!.value);
         }
+      } catch (err) {
+        cleanup();
+        reject(err);
+      }
     };
 
     process.stdin.on("data", onData);
@@ -243,15 +250,25 @@ export async function selectMany<T>(
       renderedLines,
     );
   };
-  render();
 
-  return new Promise((resolve) => {
-    const finish = (value: T[] | null | PromptBack) => {
+  const cleanup = () => {
     process.stdin.setRawMode(wasRaw === true);
     process.stdin.pause();
-      process.stdin.removeListener("data", onData);
     clearPrompt(renderedLines);
     showCursor();
+  };
+
+  try {
+    render();
+  } catch (err) {
+    cleanup();
+    throw err;
+  }
+
+  return new Promise((resolve, reject) => {
+    const finish = (value: T[] | null | PromptBack) => {
+      process.stdin.removeListener("data", onData);
+      cleanup();
       if (value === null && options.cancelMessage) {
         process.stdout.write(`  ${options.cancelMessage}\n`);
       }
@@ -259,6 +276,7 @@ export async function selectMany<T>(
     };
 
     const onData = (data: Buffer) => {
+      try {
         const result = normalizeKey(data.toString(), escapeBuf);
         escapeBuf = result.escapeBuf;
 
@@ -270,6 +288,10 @@ export async function selectMany<T>(
         else if (result.action === "enter") {
           finish(items.filter((item) => item.selected && item.value !== null).map((item) => item.value as T));
         }
+      } catch (err) {
+        cleanup();
+        reject(err);
+      }
     };
 
     process.stdin.on("data", onData);