Refactor WiFi Management to Use NetworkManager D-Bus API

[czechbol]

Summary

I had a lot of issues with the original implementation.
For example, the logic handling which password type should be used wasn't enough to connect to my home wifi, it was impossible to recover from incorrectly saved wifi passwords, authentication failure handling was insufficient which was causing the incorrectly saved passwords in the first place.

This PR refactors the Wifi commands with D-Bus calls, natively handles authentication types, while also introducing a few other improvements.

Changes

Core Refactor

• Replaced 7 nmcli shell commands with native D-Bus calls:
  • List saved networks
  • Activate existing connections
  • Connect to open networks
  • Connect with password
  • Disconnect from networks
  • Delete/forget saved networks
  • Real-time connection state monitoring

New Features

• Real-time UI updates via D-Bus signal subscriptions
• Delete saved networks without needing to connect first (major pain point resolved)
• Authentication type detection with support for Open/OEN/WEP/WPA/WPA3-SAE and notifications about enterprise network support.
• Authentication failure detection with user-friendly error messages
• Password keyring management prevents cached credentials from interfering

UX/UI Improvements

• Network list sorting: Active → Saved (by signal) → Unknown (by signal)
• Signal strength icons now display correctly (fixed -symbolic suffix mapping that were happening on my PCs running NetworkManager 1.54.1-1)
• Reactive connection state updates immediately on connection changes
• Password visibility toggle added for ease of use

[czechbol]

This should resolve #1107