Multi SIM support

Hello,

First of all, thank you for developing this application - it has been very useful for my daily needs.

I would like to suggest adding a forwarding logic that can be configured based on the source SIM card of the incoming SMS. For example:

- SIM1 -> email1@example.com
- SIM2 -> email2@example.com

This feature would significantly improve the flexibility and usability of the application.