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/postcss-js/sync.js

@@ -0,0 +1,12 @@
+let postcss = require('postcss')
+
+let processResult = require('./process-result')
+let parse = require('./parser')
+
+module.exports = function (plugins) {
+  let processor = postcss(plugins)
+  return input => {
+    let result = processor.process(input, { parser: parse, from: undefined })
+    return processResult(result)
+  }
+}