Is your feature request related to a problem? Please describe.

Android randomizes the Bluetooth tethering subnet prefix on each connection. For example, the phone might use 192.168.47.x one time and 192.168.123.x the next. This breaks bt-tether's static IP configuration which assumes 192.168.44.x.

Users with modern Android phones cannot reliably use Bluetooth tethering because the hardcoded static IP never matches the phone's randomly assigned subnet.

Describe the solution you'd like

Add an ip-method configuration option that supports:

• "auto" - Use DHCP to obtain IP from phone (works with Android)
• "manual" - Use static IP (current behavior, works with iOS)

Android should default to DHCP

Describe alternatives you've considered

1. Root the Android phone to force a specific subnet - not practical for most users
2. Detect subnet dynamically and configure static IP to match - complex and unreliable
3. Use DHCP via NetworkManager - cleanest solution, NetworkManager handles it automatically