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/@babel/preset-modules/lib/plugins/transform-safari-for-shadowing/index.js

@@ -0,0 +1,42 @@
+"use strict";
+
+exports.__esModule = true;
+exports.default = void 0;
+
+/**
+ * Safari ~11 has an issue where variable declarations in a For statement throw if they shadow parameters.
+ * This is fixed by renaming any declarations in the left/init part of a For* statement so they don't shadow.
+ * @see https://bugs.webkit.org/show_bug.cgi?id=171041
+ *
+ * @example
+ *   e => { for (let e of []) e }   // throws
+ *   e => { for (let _e of []) _e }   // works
+ */
+function handle(declaration) {
+  if (!declaration.isVariableDeclaration()) return;
+  const fn = declaration.getFunctionParent();
+  const {
+    name
+  } = declaration.node.declarations[0].id; // check if there is a shadowed binding coming from a parameter
+
+  if (fn && fn.scope.hasOwnBinding(name) && fn.scope.getOwnBinding(name).kind === "param") {
+    declaration.scope.rename(name);
+  }
+}
+
+var _default = () => ({
+  name: "transform-safari-for-shadowing",
+  visitor: {
+    ForXStatement(path) {
+      handle(path.get("left"));
+    },
+
+    ForStatement(path) {
+      handle(path.get("init"));
+    }
+
+  }
+});
+
+exports.default = _default;
+module.exports = exports.default;