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/core-js-pure/internals/detach-transferable.js

@@ -0,0 +1,37 @@
+'use strict';
+var globalThis = require('../internals/global-this');
+var getBuiltInNodeModule = require('../internals/get-built-in-node-module');
+var PROPER_STRUCTURED_CLONE_TRANSFER = require('../internals/structured-clone-proper-transfer');
+
+var structuredClone = globalThis.structuredClone;
+var $ArrayBuffer = globalThis.ArrayBuffer;
+var $MessageChannel = globalThis.MessageChannel;
+var detach = false;
+var WorkerThreads, channel, buffer, $detach;
+
+if (PROPER_STRUCTURED_CLONE_TRANSFER) {
+  detach = function (transferable) {
+    structuredClone(transferable, { transfer: [transferable] });
+  };
+} else if ($ArrayBuffer) try {
+  if (!$MessageChannel) {
+    WorkerThreads = getBuiltInNodeModule('worker_threads');
+    if (WorkerThreads) $MessageChannel = WorkerThreads.MessageChannel;
+  }
+
+  if ($MessageChannel) {
+    channel = new $MessageChannel();
+    buffer = new $ArrayBuffer(2);
+
+    $detach = function (transferable) {
+      channel.port1.postMessage(null, [transferable]);
+    };
+
+    if (buffer.byteLength === 2) {
+      $detach(buffer);
+      if (buffer.byteLength === 0) detach = $detach;
+    }
+  }
+} catch (error) { /* empty */ }
+
+module.exports = detach;