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/aria-query/lib/etc/roles/literal/tabRole.js

@@ -0,0 +1,30 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+var tabRole = {
+  abstract: false,
+  accessibleNameRequired: false,
+  baseConcepts: [],
+  childrenPresentational: true,
+  nameFrom: ['author', 'contents'],
+  prohibitedProps: [],
+  props: {
+    'aria-disabled': null,
+    'aria-expanded': null,
+    'aria-haspopup': null,
+    'aria-posinset': null,
+    'aria-setsize': null,
+    'aria-selected': 'false'
+  },
+  relatedConcepts: [],
+  requireContextRole: ['tablist'],
+  requiredContextRole: ['tablist'],
+  requiredOwnedElements: [],
+  requiredProps: {},
+  superClass: [['roletype', 'structure', 'sectionhead'], ['roletype', 'widget']]
+};
+var _default = tabRole;
+exports.default = _default;