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/index.d.ts

@@ -0,0 +1,17 @@
+import { registerQuotaErrorCallback } from './registerQuotaErrorCallback.js';
+import * as _private from './_private.js';
+import { cacheNames } from './cacheNames.js';
+import { copyResponse } from './copyResponse.js';
+import { clientsClaim } from './clientsClaim.js';
+import { setCacheNameDetails } from './setCacheNameDetails.js';
+import { skipWaiting } from './skipWaiting.js';
+import './_version.js';
+/**
+ * All of the Workbox service worker libraries use workbox-core for shared
+ * code as well as setting default values that need to be shared (like cache
+ * names).
+ *
+ * @module workbox-core
+ */
+export { _private, cacheNames, clientsClaim, copyResponse, registerQuotaErrorCallback, setCacheNameDetails, skipWaiting, };
+export * from './types.js';