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-precaching/utils/createCacheKey.d.ts

@@ -0,0 +1,17 @@
+import { PrecacheEntry } from '../_types.js';
+import '../_version.js';
+interface CacheKey {
+    cacheKey: string;
+    url: string;
+}
+/**
+ * Converts a manifest entry into a versioned URL suitable for precaching.
+ *
+ * @param {Object|string} entry
+ * @return {string} A URL with versioning info.
+ *
+ * @private
+ * @memberof workbox-precaching
+ */
+export declare function createCacheKey(entry: PrecacheEntry | string): CacheKey;
+export {};