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/webpack/lib/util/Queue.js

@@ -0,0 +1,52 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+/**
+ * @template T
+ */
+class Queue {
+	/**
+	 * @param {Iterable<T>=} items The initial elements.
+	 */
+	constructor(items) {
+		/**
+		 * @private
+		 * @type {Set<T>}
+		 */
+		this._set = new Set(items);
+	}
+
+	/**
+	 * Returns the number of elements in this queue.
+	 * @returns {number} The number of elements in this queue.
+	 */
+	get length() {
+		return this._set.size;
+	}
+
+	/**
+	 * Appends the specified element to this queue.
+	 * @param {T} item The element to add.
+	 * @returns {void}
+	 */
+	enqueue(item) {
+		this._set.add(item);
+	}
+
+	/**
+	 * Retrieves and removes the head of this queue.
+	 * @returns {T | undefined} The head of the queue of `undefined` if this queue is empty.
+	 */
+	dequeue() {
+		const result = this._set[Symbol.iterator]().next();
+		if (result.done) return;
+		this._set.delete(result.value);
+		return result.value;
+	}
+}
+
+module.exports = Queue;