Migrate linting to eslint 9 + neostandard, add engines >= 20

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

Author: perki

.eslintrc.yml

@@ -1,5 +1,5 @@
 {
-  "publicationDate": "2026-02-02T14:08:18.391Z",
+  "publicationDate": "2026-02-12T18:19:36.712Z",
   "streams": [
     {
       "id": "body",

docs/pack.json

@@ -0,0 +1,21 @@
+import neostandard from 'neostandard';
+
+export default [
+  ...neostandard({ semi: true }),
+  {
+    ignores: ['node_modules/*', 'docs/*']
+  },
+  {
+    files: ['tests/**/*.js'],
+    languageOptions: {
+      globals: {
+        describe: 'readonly',
+        it: 'readonly',
+        before: 'readonly',
+        after: 'readonly',
+        beforeEach: 'readonly',
+        afterEach: 'readonly'
+      }
+    }
+  }
+];