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/ajv/lib/cache.js

@@ -0,0 +1,26 @@
+'use strict';
+
+
+var Cache = module.exports = function Cache() {
+  this._cache = {};
+};
+
+
+Cache.prototype.put = function Cache_put(key, value) {
+  this._cache[key] = value;
+};
+
+
+Cache.prototype.get = function Cache_get(key) {
+  return this._cache[key];
+};
+
+
+Cache.prototype.del = function Cache_del(key) {
+  delete this._cache[key];
+};
+
+
+Cache.prototype.clear = function Cache_clear() {
+  this._cache = {};
+};