Feature: Migrate app hosting to Cloudflare R2 for cost-effective distribution

## Feature Request

Migrate app hosting and distribution to Cloudflare R2 to take advantage of free egress bandwidth, which is crucial for distributing large (~100MB) Electron app updates.

## Description

Cloudflare R2 offers S3-compatible object storage with ZERO egress fees, making it ideal for hosting and distributing large Electron applications. This can save significant costs compared to traditional CDNs or cloud storage providers.

## Why Cloudflare R2?

### Cost Benefits
- **FREE egress bandwidth** (huge savings for 100MB+ updates)
- 10 GB/month free storage
- Very low storage costs beyond free tier ($0.015/GB/month)
- No bandwidth charges regardless of download volume
- Predictable costs (only pay for storage)

### Technical Benefits
- S3-compatible API (easy migration)
- Global CDN included (fast downloads worldwide)
- 99.999999999% (11 9's) durability
- Automatic replication
- Direct integration with Cloudflare CDN
- Custom domain support

## Implementation Plan

### Storage Structure
```
/releases/
/stable/
/win32/
app-1.0.0-setup.exe
app-1.0.0.nupkg
RELEASES
/darwin/
app-1.0.0.dmg
app-1.0.0-mac.zip
/linux/
app-1.0.0.AppImage
app-1.0.0.deb
/beta/
...
/latest.yml
/latest-mac.yml
/latest-linux.yml
```

### Auto-Update Configuration
- Configure electron-updater to use R2 URLs
- Set up proper CORS headers
- Implement version manifest files
- Support differential updates

### CI/CD Integration
- GitHub Actions to upload to R2
- Wrangler CLI or AWS SDK (S3 compatible)
- Automated cleanup of old versions
- Backup retention policy

### CDN Configuration
- Custom domain (e.g., releases.yourapp.com)
- Cloudflare caching rules
- Cache headers optimization
- Compression settings
- Rate limiting if needed

### Migration Strategy
1. Set up R2 bucket and permissions
2. Configure Cloudflare Workers for custom logic (if needed)
3. Update electron-updater configuration
4. Implement dual publishing (GitHub + R2) initially
5. Monitor and validate R2 performance
6. Full cutover to R2
7. Keep GitHub Releases as backup/mirror

## Security & Access Control

- Signed URLs for private beta releases
- IP-based access restrictions if needed
- Cloudflare Access integration
- Download analytics and monitoring
- DDoS protection included

## Monitoring & Analytics

- Download metrics via Cloudflare Analytics
- Error tracking for failed downloads
- Geographic distribution insights
- Bandwidth usage monitoring (even though free)
- Update adoption rates

## Cost Comparison

### Traditional CDN (e.g., AWS CloudFront)
- 100MB app × 1000 downloads/month = 100GB
- Cost: ~$8.50/month (varies by region)
- 10,000 downloads = $85/month

### Cloudflare R2
- 100MB app × unlimited downloads
- Cost: $0 (free egress)
- Only pay for storage: ~$0.15 for 10GB

## Implementation Requirements

- [ ] Create Cloudflare account and R2 bucket
- [ ] Set up R2 API credentials
- [ ] Configure bucket permissions and CORS
- [ ] Update CI/CD pipeline for R2 uploads
- [ ] Modify electron-updater configuration
- [ ] Set up custom domain
- [ ] Implement version cleanup policy
- [ ] Create monitoring dashboard
- [ ] Document deployment process
- [ ] Test auto-update flow
- [ ] Plan migration timeline
- [ ] Set up backup strategy

## Acceptance Criteria

- [ ] R2 bucket is configured and accessible
- [ ] CI/CD successfully uploads releases to R2
- [ ] Auto-updater downloads from R2 successfully
- [ ] Download speeds are comparable or better
- [ ] Zero egress costs confirmed
- [ ] Monitoring and analytics are functional
- [ ] Fallback mechanism to GitHub Releases works
- [ ] Documentation is complete
- [ ] All platforms can update from R2

## Resources

- [Cloudflare R2 Documentation](https://developers.cloudflare.com/r2/)
- [R2 Pricing](https://developers.cloudflare.com/r2/pricing/)
- [electron-updater Documentation](https://www.electron.build/auto-update)

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

Locate the electron-updater configuration and the GitHub Actions workflow responsible for publishing releases, then review the proposed R2 bucket structure and migration steps. The work is done when releases upload to R2, all platforms update successfully, GitHub Releases remains a fallback, and monitoring and deployment documentation are complete.

Written by the indexing model from the issue text.