fix: resolve @babel/traverse CJS/ESM interop for native .mts execution (#590)

* fix: resolve @babel/traverse CJS/ESM interop for native .mts execution

Node's ESM loader wraps CJS modules so the default export is a namespace
object, not the function itself. Extract `.default` at runtime with a
cast to satisfy TypeScript. Also bump .node-version to 25.9.0.

* fix: use consistent @babel/traverse CJS/ESM interop pattern

Apply the same runtime-safe interop resolution in both generate-sdk.mts
and bundle-validation.test.mts. The typeof check handles both Vitest
(where the import may already be the function) and native Node ESM
(where it's wrapped under .default).

* refactor: simplify traverse interop to nullish coalescing

Author: jdalton

.node-version

@@ -1 +1 @@
-25.8.2
+25.9.0

scripts/generate-sdk.mts

@@ -15,7 +15,7 @@ import path from 'node:path'
 import process from 'node:process'
 
 import { parse } from '@babel/parser'
-import { default as traverse } from '@babel/traverse'
+import _traverse from '@babel/traverse'
 import * as t from '@babel/types'
 import MagicString from 'magic-string'
 
@@ -26,6 +26,9 @@ import { spawn } from '@socketsecurity/lib/spawn'
 import { getRootPath } from './utils/path-helpers.mts'
 import { runCommand } from './utils/run-command.mts'
 
+// CJS/ESM interop: @babel/traverse wraps the function under .default in ESM
+const traverse = ((_traverse as any).default ?? _traverse) as typeof _traverse
+
 const OPENAPI_URL = 'https://api.socket.dev/v0/openapi'
 
 const rootPath = getRootPath(import.meta.url)

test/unit/bundle-validation.test.mts

@@ -8,9 +8,12 @@ import path from 'node:path'
 import { fileURLToPath } from 'node:url'
 
 import { parse } from '@babel/parser'
-import { default as traverse } from '@babel/traverse'
+import _traverse from '@babel/traverse'
 import { describe, expect, it } from 'vitest'
 
+// CJS/ESM interop: @babel/traverse wraps the function under .default in ESM
+const traverse = ((_traverse as any).default ?? _traverse) as typeof _traverse
+
 const __dirname = path.dirname(fileURLToPath(import.meta.url))
 const packagePath = path.resolve(__dirname, '../..')
 const distPath = path.join(packagePath, 'dist')