Refactor: Complete barcodeImage to hub3aText migration across codebase

Database & Types:
- Added hub3aText field to Bill interface in db-types.ts
- Marked barcodeImage as @deprecated legacy field

Server Actions:
- Updated billActions to read/write hub3aText instead of barcodeImage
- Commented out legacy barcodeImage code with migration notes

Barcode Decoder:
- Renamed image2canvas to file2canvas for clarity
- Added new image2canvas function for base64 encoded images (migration support)
- Added hub3aText to DecodeResult type
- Exported decodeFromImage function for legacy data migration
- Updated decoding logic to extract and return hub3aText

UI Components:
- Refactored Pdf417Barcode to accept hub3aText string instead of PaymentParams
- Removed EncodePayment call from Pdf417Barcode (now expects pre-encoded text)
- Updated ViewLocationCard to encode payment params before passing to Pdf417Barcode

This completes the refactoring from storing bitmap images to storing decoded
HUB-3A payment strings, providing more efficient storage and easier data manipulation.

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

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

app/ui/Pdf417Barcode.tsx

@@ -5,16 +5,14 @@ import { generateBarcode } from '../lib/pdf/pdf417';
 import { renderBarcode } from '../lib/pdf/renderBarcode';
 import { EncodePayment, PaymentParams } from 'hub-3a-payment-encoder';
     
-export const Pdf417Barcode:FC<{paymentParams:PaymentParams}> = ({paymentParams}) => {
+export const Pdf417Barcode:FC<{hub3aText:string}> = ({hub3aText: hub3a_text}) => {
     const [bitmapData, setBitmapData] = useState<string | undefined>(undefined);
 
     useEffect(() => {
-        const hub3a_text = EncodePayment(paymentParams);
-
         const barcodeMatrix = generateBarcode(hub3a_text);
         const bitmap = renderBarcode(barcodeMatrix, 2, 2);
         setBitmapData(bitmap);
-    }, [paymentParams]);
+    }, [hub3a_text]);
 
     // Don't render until bitmap is generated (prevents hydration mismatch)
     if (!bitmapData) {