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/workbox-core/models/pluginEvents.js

@@ -0,0 +1,18 @@
+/*
+  Copyright 2018 Google LLC
+
+  Use of this source code is governed by an MIT-style
+  license that can be found in the LICENSE file or at
+  https://opensource.org/licenses/MIT.
+*/
+import '../_version.js';
+export var pluginEvents;
+(function (pluginEvents) {
+    pluginEvents["CACHE_DID_UPDATE"] = "cacheDidUpdate";
+    pluginEvents["CACHE_KEY_WILL_BE_USED"] = "cacheKeyWillBeUsed";
+    pluginEvents["CACHE_WILL_UPDATE"] = "cacheWillUpdate";
+    pluginEvents["CACHED_RESPONSE_WILL_BE_USED"] = "cachedResponseWillBeUsed";
+    pluginEvents["FETCH_DID_FAIL"] = "fetchDidFail";
+    pluginEvents["FETCH_DID_SUCCEED"] = "fetchDidSucceed";
+    pluginEvents["REQUEST_WILL_FETCH"] = "requestWillFetch";
+})(pluginEvents || (pluginEvents = {}));