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/lucide-react/dist/esm/icons/check-square.mjs

@@ -0,0 +1,19 @@
+/**
+ * lucide-react v0.0.1 - ISC
+ */
+
+import createLucideIcon from '../createLucideIcon.mjs';
+
+const CheckSquare = createLucideIcon("CheckSquare", [
+  ["polyline", { points: "9 11 12 14 22 4", key: "19ybtz" }],
+  [
+    "path",
+    {
+      d: "M21 12v7a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h11",
+      key: "1jnkn4"
+    }
+  ]
+]);
+
+export { CheckSquare as default };
+//# sourceMappingURL=check-square.mjs.map