fix(cli): deduplicate isInteractiveTTY and stop spinner on error

Extract shared isInteractiveTTY() to prompts.ts and add try/catch to
withSpinner so the spinner is stopped if the task throws, preventing
garbled terminal output on error.

Author: cameroncooke

src/cli/commands/init.ts

@@ -4,7 +4,7 @@ import * as path from 'node:path';
 import * as os from 'node:os';
 import * as clack from '@clack/prompts';
 import { getResourceRoot } from '../../core/resource-root.ts';
-import { createPrompter, type Prompter } from '../interactive/prompts.ts';
+import { createPrompter, isInteractiveTTY, type Prompter } from '../interactive/prompts.ts';
 
 type SkillType = 'mcp' | 'cli';
 
@@ -88,10 +88,6 @@ function resolveDestinationPath(inputPath: string): string {
   return path.resolve(expandHomePrefix(inputPath));
 }
 
-function isInteractiveTTY(): boolean {
-  return process.stdin.isTTY === true && process.stdout.isTTY === true;
-}
-
 async function promptConfirm(question: string): Promise<boolean> {
   if (!isInteractiveTTY()) {
     return false;

src/cli/commands/setup.ts

@@ -13,7 +13,12 @@ import {
   persistProjectConfigPatch,
   type ProjectConfig,
 } from '../../utils/project-config.ts';
-import { createPrompter, type Prompter, type SelectOption } from '../interactive/prompts.ts';
+import {
+  createPrompter,
+  isInteractiveTTY,
+  type Prompter,
+  type SelectOption,
+} from '../interactive/prompts.ts';
 import type { FileSystemExecutor } from '../../utils/FileSystemExecutor.ts';
 import type { CommandExecutor } from '../../utils/CommandExecutor.ts';
 import { createDoctorDependencies } from '../../mcp/tools/doctor/lib/doctor.deps.ts';
@@ -52,10 +57,6 @@ function showPromptHelp(helpText: string, quietOutput: boolean): void {
   clack.log.message(helpText);
 }
 
-function isInteractiveTTY(): boolean {
-  return process.stdin.isTTY === true && process.stdout.isTTY === true;
-}
-
 async function withSpinner<T>(opts: {
   isTTY: boolean;
   quietOutput: boolean;
@@ -69,9 +70,14 @@ async function withSpinner<T>(opts: {
 
   const s = clack.spinner();
   s.start(opts.startMessage);
-  const result = await opts.task();
-  s.stop(opts.stopMessage);
-  return result;
+  try {
+    const result = await opts.task();
+    s.stop(opts.stopMessage);
+    return result;
+  } catch (error) {
+    s.stop(opts.startMessage);
+    throw error;
+  }
 }
 
 function valuesEqual(left: unknown, right: unknown): boolean {

src/cli/interactive/prompts.ts

@@ -136,8 +136,12 @@ function createTtyPrompter(): Prompter {
   };
 }
 
+export function isInteractiveTTY(): boolean {
+  return process.stdin.isTTY === true && process.stdout.isTTY === true;
+}
+
 export function createPrompter(): Prompter {
-  if (!process.stdin.isTTY || !process.stdout.isTTY) {
+  if (!isInteractiveTTY()) {
     return createNonInteractivePrompter();
   }