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/enhanced-resolve/lib/NextPlugin.js

@@ -0,0 +1,33 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+/** @typedef {import("./Resolver")} Resolver */
+/** @typedef {import("./Resolver").ResolveStepHook} ResolveStepHook */
+
+module.exports = class NextPlugin {
+	/**
+	 * @param {string | ResolveStepHook} source source
+	 * @param {string | ResolveStepHook} target target
+	 */
+	constructor(source, target) {
+		this.source = source;
+		this.target = target;
+	}
+
+	/**
+	 * @param {Resolver} resolver the resolver
+	 * @returns {void}
+	 */
+	apply(resolver) {
+		const target = resolver.ensureHook(this.target);
+		resolver
+			.getHook(this.source)
+			.tapAsync("NextPlugin", (request, resolveContext, callback) => {
+				resolver.doResolve(target, request, null, resolveContext, callback);
+			});
+	}
+};