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/resolve-url-loader/lib/join-function/fs-utils.js

@@ -0,0 +1,24 @@
+/*
+ * MIT License http://opensource.org/licenses/MIT
+ * Author: Ben Holloway @bholloway
+ */
+'use strict';
+
+const fsUtils = (fs) => {
+  // fs from enhanced-resolver doesn't include fs.existsSync so we need to use fs.statsSync instead
+  const withStats = (fn) => (absolutePath) => {
+    try {
+      return fn(fs.statSync(absolutePath));
+    } catch (e) {
+      return false;
+    }
+  };
+
+  return {
+    isFileSync: withStats((stats) => stats.isFile()),
+    isDirectorySync: withStats((stats) => stats.isDirectory()),
+    existsSync: withStats((stats) => stats.isFile() || stats.isDirectory())
+  };
+};
+
+module.exports = fsUtils;