Add support for TLS enabled servers

Hey Dustin 👋, I've added TLS support to the [latest Mobius release](https://github.com/jhalter/mobius/releases/tag/v0.20.0) and with the changes in this PR, it seems to be working with your client! TLS can be enabled with this new toggle in the server connect and bookmark views: <img width="892" height="752" alt="Screenshot 2025-11-22 at 8 08 17 PM" src="https://github.com/user-attachments/assets/6b0c30ef-efdb-4bfc-9140-3b943a87428b" /> When enabled, transactions and file transfers go through the TLS encrypted connections. I'm currently running TLS on mobius.trtphotl.com:5600 with a valid Let's Encrypt certificate if you'd like to test it out. I need to test out some of the unhappy path scenarios (e.g. invalid cert), but I wanted to share this seemingly working implementation! 🎉