chore: export BUILD_CRITICAL_PACKAGES for the test, drop dead default export

Follow-up to the salvaged #87980: the test kept its own copy of the
build-critical package list (drift hazard) and the module's default
export had no consumer.

apps/desktop/scripts/assert-root-install.mjs

@@ -32,6 +32,7 @@ import { isMain } from "./utils.mjs"
 // an unresolved `katex/dist/katex.min.css` with no hint that the install — not
 // the source — was at fault (#86443).
 const BUILD_CRITICAL_PACKAGES = ["vite", "katex", "electron", "electron-builder"]
+export { BUILD_CRITICAL_PACKAGES }
 
 // Resolve the way Node's own lookup does — walk `node_modules` upward — rather
 // than through `require.resolve`. A package whose `exports` map does not expose
@@ -114,5 +115,3 @@ function main() {
 if (isMain(import.meta.url)) {
   main()
 }
-
-export default { checkRootInstall }

apps/desktop/scripts/assert-root-install.test.mjs

@@ -4,9 +4,7 @@ import os from 'node:os'
 import path from 'node:path'
 import { test } from 'vitest'
 
-import { checkRootInstall } from '../scripts/assert-root-install.mjs'
-
-const BUILD_CRITICAL = ['vite', 'katex', 'electron', 'electron-builder']
+import { BUILD_CRITICAL_PACKAGES as BUILD_CRITICAL, checkRootInstall } from '../scripts/assert-root-install.mjs'
 
 // Build a throwaway repo shaped like this one: an app workspace whose
 // dependencies are hoisted to the repo root, which is what the guard walks.