Build a QR code generator:
- Input types: URL, plain text, WiFi credentials, vCard contact, email, phone
- Customize: size, color, background color, error correction level
- Add a logo/image in the center
- Download as PNG or SVG
- Batch generation from a list
- History of generated codes (localStorage)
Use a QR code library (qrcode.js or similar via CDN). Clean, focused UI. Put in ~/data/public/