Fix ESLint warnings for img elements

Add ESLint disable comments for @next/next/no-img-element warnings where appropriate (barcode images with base64 data URIs don't benefit from Next.js Image optimization) and add missing alt attribute to PDF417 barcode component.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/ui/PrintPreview.tsx

@@ -136,7 +136,9 @@ export const PrintPreview: React.FC<PrintPreviewProps> = ({ data, year, month, t
                         <Pdf417Barcode hub3aText={item.hub3aText} className="max-h-28 w-auto max-w-[270px] print:m-[5em_auto] print:h-[auto] print:max-h-[85px] print:w-[69.6mm] print:max-w-[69.6mm]" />
                         : (
                           // LEGACY SUPPORT ... untill all bills have been migrated
+                          
                           item.barcodeImage ?
+                            // eslint-disable-next-line @next/next/no-img-element
                             <img
                               src={item.barcodeImage.startsWith('data:') ? item.barcodeImage : `data:image/png;base64,${item.barcodeImage}`}
                               alt={`Barcode for ${item.billName}`}