Add GitHub workflow for PDF generation using Playwright

Create a workflow that generates a DIN A4 PDF of the print version
of index.html and stores it as an artifact. Uses Playwright with
Chromium to load the page, wait for QR codes to render, and
generate the PDF.

package.json

@@ -0,0 +1,12 @@
+{
+  "name": "asn-qr-code-label-generator",
+  "version": "1.0.0",
+  "description": "QR code label generator for Paperless-ngx Archive Serial Numbers",
+  "private": true,
+  "scripts": {
+    "generate-pdf": "node scripts/generate-pdf.js"
+  },
+  "devDependencies": {
+    "playwright": "^1.49.0"
+  }
+}