Add QR code support to bulk label generation

[emares17]

Summary

• Users can now select Code 128 or QR Code as the barcode type before generating label sheets
• QR codes render as native ReportLab vector graphics (QrCodeWidget) - no new dependencies, no PNG intermediate, same performance as Code 128
• barcode_type is threaded through the full pipeline: upload route -> label service -> PDF sheet generator -> barcode generator
• Invalid barcode_type values from the frontend default to code128 for safety

Files changed

• backend/utils/BarcodeGenerator.py - QR drawing logic via QrCodeWidget, calibrate() skipped for QR (self-sizing)
• backend/utils/PDFSheetGenerator.py - barcode_type param added to generate_pdf_sheets()
• backend/services/label_service.py - barcode_type param added to process_label_file()
• backend/routes/uploads.py - extracts and validates barcode_type from form data
• frontend-vite/react-ts/src/components/labelUploader.tsx - barcode type toggle UI + appended to formData

Test plan

• Upload a CSV, select QR Code, generate - confirm PDF shows QR codes
• Scan a generated QR label with a phone - confirm it resolves to the correct value
• Switch back to Code 128 on the same file - confirm existing behavior unchanged
• Test all 4 label templates with QR selected - confirm QR codes are centered and text lines appear below
• Test with a long string value - confirm QR still fits within label bounds

Generated with Claude Code

[railway-app]

🚅 Deployed to the BarcodeGenerator-pr-8 environment in LabelGenius

Service	Status	Web	Updated (UTC)
LabelGenius-Backend	✅ Success (View Logs)	Web	Apr 22, 2026 at 9:14 pm
LabelGenius-Frontend	✅ Success (View Logs)	Web	Apr 22, 2026 at 9:14 pm