Initial commit: Developer Tools MVP with visual editor

- Complete React app with 7 developer tools
- JSON Tool with visual structured editor
- Serialize Tool with visual structured editor
- URL, Base64, CSV/JSON, Beautifier, Diff tools
- Responsive navigation with dropdown menu
- Dark/light mode toggle
- Mobile-responsive design with sticky header
- All tools working with copy/paste functionality

node_modules/eslint-module-utils/visit.js

@@ -0,0 +1,30 @@
+'use strict';
+
+exports.__esModule = true;
+
+/** @type {import('./visit').default} */
+exports.default = function visit(node, keys, visitorSpec) {
+  if (!node || !keys) {
+    return;
+  }
+  const type = node.type;
+  const visitor = visitorSpec[type];
+  if (typeof visitor === 'function') {
+    visitor(node);
+  }
+  const childFields = keys[type];
+  if (!childFields) {
+    return;
+  }
+  childFields.forEach((fieldName) => {
+    // @ts-expect-error TS sucks with concat
+    [].concat(node[fieldName]).forEach((item) => {
+      visit(item, keys, visitorSpec);
+    });
+  });
+
+  const exit = visitorSpec[`${type}:Exit`];
+  if (typeof exit === 'function') {
+    exit(node);
+  }
+};