Adjust PDF margins to 10mm (matching local print preview)

server.js

@@ -55,10 +55,10 @@ app.post('/api/generate_pdf', async (req, res) => {
       format: 'A4',
       printBackground: true,
       margin: {
-        top: '15mm',
-        bottom: '15mm',
-        left: '5mm',
-        right: '5mm'
+        top: '10mm',
+        bottom: '10mm',
+        left: '10mm',
+        right: '10mm'
       }
     });