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/sucrase/dist/esm/NameManager.js

@@ -0,0 +1,27 @@
+
+import getIdentifierNames from "./util/getIdentifierNames";
+
+export default class NameManager {
+    __init() {this.usedNames = new Set()}
+
+  constructor(code, tokens) {;NameManager.prototype.__init.call(this);
+    this.usedNames = new Set(getIdentifierNames(code, tokens));
+  }
+
+  claimFreeName(name) {
+    const newName = this.findFreeName(name);
+    this.usedNames.add(newName);
+    return newName;
+  }
+
+  findFreeName(name) {
+    if (!this.usedNames.has(name)) {
+      return name;
+    }
+    let suffixNum = 2;
+    while (this.usedNames.has(name + String(suffixNum))) {
+      suffixNum++;
+    }
+    return name + String(suffixNum);
+  }
+}