feat(v1.2.0): add QR scanner with camera/upload support

- Add QRScanner component with camera and image upload
- Add QR code download button with auto-naming (SeedPGP_DATE_TIME.png)
- Split state for backup/restore (separate public/private keys and passwords)
- Improve QR generation settings (margin: 4, errorCorrection: M)
- Fix Safari camera permissions and Continuity Camera support
- Add React timing fix for Html5Qrcode initialization
- Configure Vite for GitHub Pages deployment
- Update deploy script for dist as public repo
- Update public README for v1.2.0 features

Features:
- Camera scanning with live preview and Continuity Camera
- Image file upload scanning
- Automatic SEEDPGP1 validation
- 512x512px high-quality QR generation with download
- User-friendly error messages

public/README.md

@@ -1,48 +1,124 @@
 # SeedPGP Web App
 
-**Secure BIP39 mnemonic backup tool using PGP encryption**
+**Secure BIP39 mnemonic backup tool using OpenPGP encryption**
 
 🔗 **Live App**: https://kccleoc.github.io/seedpgp-web-app/
 
 ## About
 
-This is a client-side web application for encrypting cryptocurrency seed phrases (BIP39 mnemonics) using OpenPGP encryption and Base45 encoding for QR code generation.
+Client-side web application for encrypting cryptocurrency seed phrases (BIP39 mnemonics) using OpenPGP encryption with QR code generation and scanning capabilities.
 
-### Features
+### ✨ Features
 
-- 🔐 PGP encryption with cv25519 (Curve25519)
-- 📱 QR code-ready output (Base45 + CRC16)
-- ✅ Supports 12/18/24-word BIP39 mnemonics
-- 🔒 All encryption happens in your browser (client-side only)
+- 🔐 **OpenPGP Encryption** - Curve25519Legacy (cv25519) encryption
+- 📱 **QR Code Generation** - High-quality 512x512px PNG with download
+- 📸 **QR Code Scanner** - Camera or image upload with live preview
+- 🔄 **Round-trip Flow** - Encrypt → QR → Scan → Decrypt seamlessly
+- ✅ **BIP39 Support** - 12/18/24-word mnemonics with optional passphrase
+- 🔒 **Symmetric Encryption** - Optional password-only encryption (SKESK)
+- 🎯 **CRC16 Validation** - Frame integrity checking
+- 📦 **Base45 Encoding** - Compact QR-friendly format (RFC 9285)
+- 🌐 **100% Client-Side** - No backend, no data transmission
 
-## Security Notice
+## 🔒 Security Notice
 
 ⚠️ **Your private keys and seed phrases never leave your browser**
 
-- This is a static web app with no backend server
-- All cryptographic operations run locally in your browser
-- No data is transmitted to any server
+- Static web app with **no backend server**
+- All cryptographic operations run **locally in your browser**
+- **No data transmitted** to any server
+- Camera access requires **HTTPS or localhost**
 - Always verify you're on the correct URL before use
 
 ### For Maximum Security
 
 For production use with real funds:
-- Download and run locally
-- Or use a self-hosted version
-- Source code: https://github.com/kccleoc/seedpgp-web
+- 🏠 Download and run locally (`bun run dev`)
+- 🔐 Use on airgapped device
+- 📥 Self-host on your own domain
+- 🔍 Source code: https://github.com/kccleoc/seedpgp-web (private)
 
-## How to Use
+## 📖 How to Use
 
-1. **Encrypt**: Enter your mnemonic + PGP public key → Get QR code
-2. **Decrypt**: Scan QR code + provide private key → Recover mnemonic
+### Backup Flow
+1. **Enter** your 12/24-word BIP39 mnemonic
+2. **Add** PGP public key and/or message password (optional)
+3. **Generate** encrypted QR code
+4. **Download** or scan QR code for backup
 
-## Version
+### Restore Flow
+1. **Scan QR Code** using camera or upload image
+2. **Provide** private key and/or message password
+3. **Decrypt** to recover your mnemonic
 
-Current deployment: **v1.1.0**
+### QR Scanner Features
+- 📷 **Camera Mode** - Live scanning with environment camera (iPhone Continuity Camera supported on macOS)
+- 📁 **Upload Mode** - Scan from saved images or screenshots
+- ✅ **Auto-validation** - Verifies SEEDPGP1 format before accepting
 
-Last updated: 2026-01-28
+## 🛠 Technical Stack
+
+- **TypeScript** - Type-safe development
+- **React 18** - Modern UI framework
+- **Vite 6** - Lightning-fast build tool
+- **OpenPGP.js v6** - RFC 4880 compliant encryption
+- **html5-qrcode** - QR scanning library
+- **TailwindCSS** - Utility-first styling
+- **Lucide React** - Beautiful icons
+
+## 📋 Protocol Format
+
+```
+SEEDPGP1:0:ABCD:BASE45DATA
+
+SEEDPGP1 - Protocol identifier + version
+0        - Frame number (single frame)
+ABCD     - CRC16-CCITT-FALSE checksum
+BASE45   - Base45-encoded OpenPGP binary message
+```
+
+## 🔐 Encryption Details
+
+- **Algorithm**: AES-256 (preferred symmetric cipher)
+- **Curve**: Curve25519Legacy for modern security
+- **Key Format**: OpenPGP RFC 4880 compliant
+- **Error Correction**: QR Level M (15% recovery)
+- **Integrity**: CRC16-CCITT-FALSE frame validation
+
+## 📱 Browser Compatibility
+
+- ✅ Chrome/Edge (latest)
+- ✅ Safari 16+ (macOS/iOS)
+- ✅ Firefox (latest)
+- 📷 Camera requires HTTPS or localhost
+
+## 📦 Version
+
+**Current deployment: v1.2.0**
+
+### Changelog
+
+#### v1.2.0 (2026-01-29)
+- ✨ Added QR scanner with camera/upload support
+- 📥 Added QR code download with auto-naming
+- 🔧 Split state for backup/restore tabs
+- 🎨 Improved QR generation quality
+- 🐛 Fixed Safari camera permissions
+- 📱 Added Continuity Camera support
+
+#### v1.1.0 (2026-01-28)
+- 🎉 Initial public release
+- 🔐 OpenPGP encryption/decryption
+- 📱 QR code generation
+- ✅ BIP39 validation
 
 ---
 
-Built with TypeScript, React, Vite, and OpenPGP.js v6
+**Last updated**: 2026-01-29
 
+**Built with** ❤️ using TypeScript, React, Vite, and OpenPGP.js
+
+**License**: Private source code - deployment only
+
+
+🚀