Proxy mode changes:
- Replace transparent TCP proxy with TLS-terminating proxy
- Slicer connects to Bambuddy cert, Bambuddy connects to printer
- Use real printer's serial number for SSDP and certificate
- This ensures MQTT topic subscriptions match the real printer
The proxy now:
1. Accepts TLS from slicer using Bambuddy's certificate
2. Opens TLS connection to real printer
3. Forwards decrypted data bidirectionally
Also: Complete i18n localization for VirtualPrinterSettings component