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/resolve-url-loader/lib/log-to-test-harness.js

@@ -0,0 +1,36 @@
+/*
+ * MIT License http://opensource.org/licenses/MIT
+ * Author: Ben Holloway @bholloway
+ */
+'use strict';
+
+var stream = require('stream');
+
+var hasLogged = false;
+
+function logToTestHarness(maybeStream, options) {
+  var doLogging =
+    !hasLogged &&
+    !!maybeStream &&
+    (typeof maybeStream === 'object') &&
+    (maybeStream instanceof stream.Writable);
+
+  if (doLogging) {
+    hasLogged = true; // ensure we log only once
+    Object.keys(options).forEach(eachOptionKey);
+  }
+
+  function eachOptionKey(key) {
+    maybeStream.write(key + ': ' + stringify(options[key]) + '\n');
+  }
+
+  function stringify(value) {
+    try {
+      return JSON.stringify(value) || String(value);
+    } catch (e) {
+      return '-unstringifyable-';
+    }
+  }
+}
+
+module.exports = logToTestHarness;