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/mini-css-extract-plugin/dist/hmr/normalize-url.js

@@ -0,0 +1,39 @@
+"use strict";
+
+/* eslint-disable */
+
+/**
+ * @param {string[]} pathComponents
+ * @returns {string}
+ */
+function normalizeUrl(pathComponents) {
+  return pathComponents.reduce(function (accumulator, item) {
+    switch (item) {
+      case "..":
+        accumulator.pop();
+        break;
+      case ".":
+        break;
+      default:
+        accumulator.push(item);
+    }
+    return accumulator;
+  }, /** @type {string[]} */[]).join("/");
+}
+
+/**
+ * @param {string} urlString
+ * @returns {string}
+ */
+module.exports = function (urlString) {
+  urlString = urlString.trim();
+  if (/^data:/i.test(urlString)) {
+    return urlString;
+  }
+  var protocol = urlString.indexOf("//") !== -1 ? urlString.split("//")[0] + "//" : "";
+  var components = urlString.replace(new RegExp(protocol, "i"), "").split("/");
+  var host = components[0].toLowerCase().replace(/\.$/, "");
+  components[0] = "";
+  var path = normalizeUrl(components);
+  return protocol + host + path;
+};