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/contextCompat.js

@@ -0,0 +1,72 @@
+'use strict';
+
+exports.__esModule = true;
+
+/** @type {import('./contextCompat').getAncestors} */
+function getAncestors(context, node) {
+  const sourceCode = getSourceCode(context);
+
+  if (sourceCode && sourceCode.getAncestors) {
+    return sourceCode.getAncestors(node);
+  }
+
+  return context.getAncestors();
+}
+
+/** @type {import('./contextCompat').getDeclaredVariables} */
+function getDeclaredVariables(context, node) {
+  const sourceCode = getSourceCode(context);
+
+  if (sourceCode && sourceCode.getDeclaredVariables) {
+    return sourceCode.getDeclaredVariables(node);
+  }
+
+  return context.getDeclaredVariables(node);
+}
+
+/** @type {import('./contextCompat').getFilename} */
+function getFilename(context) {
+  if ('filename' in context) {
+    return context.filename;
+  }
+
+  return context.getFilename();
+}
+
+/** @type {import('./contextCompat').getPhysicalFilename} */
+function getPhysicalFilename(context) {
+  if (context.getPhysicalFilename) {
+    return context.getPhysicalFilename();
+  }
+
+  return getFilename(context);
+}
+
+/** @type {import('./contextCompat').getScope} */
+function getScope(context, node) {
+  const sourceCode = getSourceCode(context);
+
+  if (sourceCode && sourceCode.getScope) {
+    return sourceCode.getScope(node);
+  }
+
+  return context.getScope();
+}
+
+/** @type {import('./contextCompat').getSourceCode} */
+function getSourceCode(context) {
+  if ('sourceCode' in context) {
+    return context.sourceCode;
+  }
+
+  return context.getSourceCode();
+}
+
+module.exports = {
+  getAncestors,
+  getDeclaredVariables,
+  getFilename,
+  getPhysicalFilename,
+  getScope,
+  getSourceCode,
+};