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/prompts/lib/dateparts/datepart.js

@@ -0,0 +1,35 @@
+'use strict';
+
+class DatePart {
+  constructor({token, date, parts, locales}) {
+    this.token = token;
+    this.date = date || new Date();
+    this.parts = parts || [this];
+    this.locales = locales || {};
+  }
+
+  up() {}
+
+  down() {}
+
+  next() {
+    const currentIdx = this.parts.indexOf(this);
+    return this.parts.find((part, idx) => idx > currentIdx && part instanceof DatePart);
+  }
+
+  setTo(val) {}
+
+  prev() {
+    let parts = [].concat(this.parts).reverse();
+    const currentIdx = parts.indexOf(this);
+    return parts.find((part, idx) => idx > currentIdx && part instanceof DatePart);
+  }
+
+  toString() {
+    return String(this.date);
+  }
+}
+
+module.exports = DatePart;
+
+