fix(windows): probe fnm's real default alias dir for Node fallback (#11359)

* fix(windows): probe fnm's real default alias dir for Node fallback

On Windows, fnm stores the default alias under FNM_DIR, else
%APPDATA%\fnm (legacy ~\.fnm), and node.exe sits directly in
aliases\default with no bin subdir. Probe those dirs and append them to
PATH so fnm's default only backfills a missing Node instead of shadowing
an inherited one.

Fixes #11356

Co-authored-by: niceSprite <16523864+iFwu@users.noreply.github.com>
Co-authored-by: Claude <noreply@anthropic.com>

* test: keep onTestFinished callbacks returning void

---------

Co-authored-by: Neil <neil@stably.ai>
Co-authored-by: Claude <noreply@anthropic.com>

src/shared/node-cli-command-resolution.ts

@@ -2,6 +2,7 @@ import { accessSync, constants, existsSync, readFileSync, readdirSync, statSync
 import { homedir } from 'node:os'
 import { delimiter, dirname, isAbsolute, join } from 'node:path'
 import { firstWindowsPathEnvKey, isNativeExecutable } from './cli-runtime-pairing-inputs'
+import { getFnmDefaultAliasDirectories } from './fnm-default-alias-dirs'
 import { getSystemCliInstallDirectories } from './system-cli-install-dirs'
 
 type ResolveCommandOptions = {
@@ -93,7 +94,7 @@ function getBaseVersionManagerDirectories(platform: NodeJS.Platform, homePath: s
   const directories = [
     join(homePath, '.volta', 'bin'),
     join(homePath, '.asdf', 'shims'),
-    join(homePath, '.fnm', 'aliases', 'default', 'bin'),
+    ...getFnmDefaultAliasDirectories(platform, homePath),
     join(homePath, '.local', 'share', 'mise', 'shims')
   ]