feat: Gluetun VPN integration and remote service enhancements
Major features:
- Native Docker-based Gluetun VPN proxy provider with multi-provider support
(NordVPN, Windscribe, Surfshark, ExpressVPN, and 50+ more)
- Stateless remote service architecture with local session caching
- Client-side authentication for remote services (browser, 2FA, OAuth support)
Key changes:
- core/proxies/windscribevpn.py: Enhanced proxy handling
- core/crypto.py: Cryptographic utilities
- docs/VPN_PROXY_SETUP.md: Comprehensive VPN/proxy documentation
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