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/istanbul-reports/lib/lcov/index.js

@@ -0,0 +1,33 @@
+'use strict';
+/*
+ Copyright 2012-2015, Yahoo Inc.
+ Copyrights licensed under the New BSD License. See the accompanying LICENSE file for terms.
+ */
+const { ReportBase } = require('istanbul-lib-report');
+const LcovOnlyReport = require('../lcovonly');
+const HtmlReport = require('../html');
+
+class LcovReport extends ReportBase {
+    constructor(opts) {
+        super();
+        this.lcov = new LcovOnlyReport({ file: 'lcov.info', ...opts });
+        this.html = new HtmlReport({ subdir: 'lcov-report' });
+    }
+}
+
+['Start', 'End', 'Summary', 'SummaryEnd', 'Detail'].forEach(what => {
+    const meth = 'on' + what;
+    LcovReport.prototype[meth] = function(...args) {
+        const lcov = this.lcov;
+        const html = this.html;
+
+        if (lcov[meth]) {
+            lcov[meth](...args);
+        }
+        if (html[meth]) {
+            html[meth](...args);
+        }
+    };
+});
+
+module.exports = LcovReport;