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-import/lib/data-url.js

@@ -0,0 +1,17 @@
+"use strict"
+
+const dataURLRegexp = /^data:text\/css;base64,/i
+
+function isValid(url) {
+  return dataURLRegexp.test(url)
+}
+
+function contents(url) {
+  // "data:text/css;base64,".length === 21
+  return Buffer.from(url.slice(21), "base64").toString()
+}
+
+module.exports = {
+  isValid,
+  contents,
+}