feat: implement build system and development workflow

- Add npm scripts for CSS/JS compilation (build:css, build:js, build)
- Create PowerShell build automation script
- Document development workflow in README
- Add troubleshooting guide for build issues
- Specify proper file structure and compilation process

Supports Tailwind CSS v3.4.0 and esbuild bundling with source maps.

node_modules/postcss-js/async.js

@@ -0,0 +1,15 @@
+let postcss = require('postcss')
+
+let processResult = require('./process-result')
+let parse = require('./parser')
+
+module.exports = function async(plugins) {
+  let processor = postcss(plugins)
+  return async input => {
+    let result = await processor.process(input, {
+      parser: parse,
+      from: undefined
+    })
+    return processResult(result)
+  }
+}