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/cacheNames.d.ts

@@ -0,0 +1,24 @@
+import './_version.js';
+/**
+ * Get the current cache names and prefix/suffix used by Workbox.
+ *
+ * `cacheNames.precache` is used for precached assets,
+ * `cacheNames.googleAnalytics` is used by `workbox-google-analytics` to
+ * store `analytics.js`, and `cacheNames.runtime` is used for everything else.
+ *
+ * `cacheNames.prefix` can be used to retrieve just the current prefix value.
+ * `cacheNames.suffix` can be used to retrieve just the current suffix value.
+ *
+ * @return {Object} An object with `precache`, `runtime`, `prefix`, and
+ *     `googleAnalytics` properties.
+ *
+ * @memberof workbox-core
+ */
+declare const cacheNames: {
+    readonly googleAnalytics: string;
+    readonly precache: string;
+    readonly prefix: string;
+    readonly runtime: string;
+    readonly suffix: string;
+};
+export { cacheNames };