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/reusify/reusify.js

@@ -0,0 +1,33 @@
+'use strict'
+
+function reusify (Constructor) {
+  var head = new Constructor()
+  var tail = head
+
+  function get () {
+    var current = head
+
+    if (current.next) {
+      head = current.next
+    } else {
+      head = new Constructor()
+      tail = head
+    }
+
+    current.next = null
+
+    return current
+  }
+
+  function release (obj) {
+    tail.next = obj
+    tail = obj
+  }
+
+  return {
+    get: get,
+    release: release
+  }
+}
+
+module.exports = reusify