[Feature request] CLI arguments for auto-connection on GUI startup and keyboard navigation improvements #3737

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

Currently, when launching the MeshCore GUI application (e.g., via AppImage on Linux), users have to manually click the "Connect" button and then select the USB/Serial device every single time.

Automating this process under modern Linux display servers like Wayland is extremely difficult. Tools like xdotool trigger security prompts ("Remote Desktop / Allow Remote Control") when trying to simulate mouse clicks, and the main GUI window does not respond to standard keyboard navigation (like Tab or Spacebar) to activate the "Connect" button.

Describe the solution you'd like

It would be incredibly helpful to have the following features implemented in the GUI client:

1. CLI Arguments for Auto-Connect on Startup:
   Allow passing parameters to the GUI app to immediately establish a connection to a specific serial port upon launch. For example:
   meshcore --gui --serial /dev/ttyACM0 or meshcore --source-type=companion --transport=usb --path=/dev/ttyACM0 --auto-connect

2. Keyboard Navigation Fix for the Main Screen:
   Make the "Connect" button focusable so that it can be triggered using the Enter or Spacebar keys right after the window opens.

3. Fallback Configuration:
   Alternatively, add a toggle in the application settings menu: "Automatically connect to the last used device on startup".

Describe alternatives you've considered

I tried using background CLI processes and connecting the GUI via --connect-to, but it launches duplicate windows and doesn't seamlessly integrate with the primary user interface state.

Additional context

Operating System: Ubuntu 24.04 / 26.04 LTS (GNOME, Wayland session).
Hardware: Pro Micro (nRF52840 / SX1262) board connected via USB serial ports (/dev/ttyACM0 / /dev/ttyACM1).