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/rollup-plugin-terser/rollup-plugin-terser.d.ts

@@ -0,0 +1,11 @@
+import { Plugin } from "rollup";
+import { MinifyOptions } from "terser";
+
+export interface Options extends Omit<MinifyOptions, "sourceMap"> {
+  /**
+   * Amount of workers to spawn. Defaults to the number of CPUs minus 1.
+   */
+  numWorkers?: number;
+}
+
+export declare function terser(options?: Options): Plugin;