fix(init): guard against missing sanity binary before dataset import

Add fs.access check before spawning the sanity binary for dataset
import. Gives a clear error message instead of a raw ENOENT if
dependencies weren't installed correctly.

Also fix misleading vitest config comment.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: rexxars

packages/@sanity/cli/src/actions/init/initStudio.ts

@@ -1,3 +1,4 @@
+import fs from 'node:fs/promises'
 import path from 'node:path'
 import {styleText} from 'node:util'
 
@@ -108,6 +109,14 @@ export async function initStudio({
     // Spawn the project's own sanity binary for dataset import.
     // The full CLI is available as a project dependency after scaffoldAndInstall.
     const sanityBin = path.join(outputPath, 'node_modules', '.bin', 'sanity')
+    try {
+      await fs.access(sanityBin)
+    } catch {
+      throw new InitError(
+        `Could not find sanity binary at "${sanityBin}". ` +
+          'Dependencies may not have been installed correctly.',
+      )
+    }
     await execa(
       sanityBin,
       [

packages/create-sanity/vitest.config.ts

@@ -6,7 +6,7 @@ export default defineConfig({
       exclude: ['**/dist/**', '**/test/**', '**/*.{test,spec}.{js,ts}'],
       provider: 'istanbul',
     },
-    disableConsoleIntercept: true, // helps oclif test helpers
+    disableConsoleIntercept: true, // tests spawn subprocesses that write to stdout/stderr
     environment: 'node',
     exclude: ['**/node_modules/**', '**/dist/**'],
     globals: false,