fix(#1): add Node.js globals to ESLint config

ESLint 9 flat config requires explicit globals. Without them, Node.js
builtins (fetch, crypto, setTimeout, AbortController, etc.) trigger
no-undef errors, blocking the CI pipeline.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

eslint.config.js

@@ -1,4 +1,5 @@
 import eslint from '@eslint/js';
+import globals from 'globals';
 import tseslint from '@typescript-eslint/eslint-plugin';
 import tsparser from '@typescript-eslint/parser';
 
@@ -12,6 +13,9 @@ export default [
         ecmaVersion: 2022,
         sourceType: 'module',
       },
+      globals: {
+        ...globals.nodeBuiltin,
+      },
     },
     plugins: {
       '@typescript-eslint': tseslint,