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/ViewBillCard.tsx

@@ -71,6 +71,7 @@ export const ViewBillCard:FC<ViewBillCardProps> = ({ location, bill }) => {
                         barcodeImage ?
                         <div className="p-1">
                             <label className="label p-2 grow bg-white border border-gray-300 rounded-box justify-center">
+                                {/* eslint-disable-next-line @next/next/no-img-element */}
                                 <img src={barcodeImage} className="grow sm:max-w-[350px]" alt="2D Barcode" />
                             </label>
                             <p className="text-xs my-1">{t.rich('barcode-disclaimer', { br: () => <br /> })}</p>