Add page-specific JavaScript support

Update documentation for new JS variables and rendering pipeline

Add script.js file support to content directories

Implement cache-busting for JavaScript files

Update static file serving to include JavaScript files

Document page-specific script loading in base.php

docs/02-tutorial/02-styling.md

@@ -241,6 +241,33 @@ FolderWeb automatically loads and includes page-specific styles with cache-busti
 <link rel="stylesheet" href="/portfolio/styles.css?v=abc123def">
 ```
 
+## Page-Specific Scripts
+
+For small progressive enhancements, you can add a `script.js` file to a content directory:
+
+```
+content/portfolio/
+├── index.md
+├── styles.css
+└── script.js
+```
+
+**script.js:**
+```js
+// Small enhancement for this page only
+document.querySelector('.portfolio-grid')?.addEventListener('click', (e) => {
+  // ...
+});
+```
+
+FolderWeb automatically loads the script with `defer` (non-blocking) and cache-busting:
+
+```html
+<script defer src="/portfolio/script.js?v=abc123def"></script>
+```
+
+The script tag is placed before `</body>`, so it runs after the page has been parsed. This is ideal for progressive enhancement — the page works without JavaScript, but gets enhanced when it's available.
+
 ## Dark Mode
 
 Add dark mode with CSS variables and `prefers-color-scheme`: