add screenshot script

line-segment-intersection/CLAUDE.md

@@ -19,6 +19,16 @@ npm run build
 npm run preview
 ```
 
+## Scripts
+
+The `script/` folder contains utility scripts for development:
+
+- **screenshot**: Captures a screenshot of the running dev server (localhost:5173) using Chrome headless mode
+  - Outputs to `screenshot.png` in the project root
+  - Requires Chrome/Chromium to be installed
+  - Dev server must be running before executing
+  - Usage: `./script/screenshot`
+
 ## Architecture
 
 ### Application Structure