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/transformers/OptionalCatchBindingTransformer.js

@@ -0,0 +1,19 @@
+
+import {TokenType as tt} from "../parser/tokenizer/types";
+
+import Transformer from "./Transformer";
+
+export default class OptionalCatchBindingTransformer extends Transformer {
+  constructor( tokens,  nameManager) {
+    super();this.tokens = tokens;this.nameManager = nameManager;;
+  }
+
+  process() {
+    if (this.tokens.matches2(tt._catch, tt.braceL)) {
+      this.tokens.copyToken();
+      this.tokens.appendCode(` (${this.nameManager.claimFreeName("e")})`);
+      return true;
+    }
+    return false;
+  }
+}