feat: add RGB controls with fake suspend integration

[antnyhills]

This PR adds RGB configuration controls to the Armada Control Decky plugin and fake-suspend script.

Key Features:

• Adds a new "RGB Settings" tab in the UI using standard gamepad-friendly sliders (R, G, B, Brightness) and sync options.
• Designed to be hardware-agnostic: Dynamically scans /sys/class/leds/ at runtime. It automatically detects and supports both the unified Linux multicolor framework (used by AYN Odin 2 / Thor) and individual single-channel LED configurations (used by AYN Odin 3).
• Gracefully degrades: If a device does not have RGB hardware or standard sysfs entries, the discovery system returns empty and ignores writes without throwing errors or crashing the plugin.
• Updates fake-suspend to dynamically detect and turn off all active RGB/joystick LEDs when entering fake suspend, and cleanly restores their previous states on wake.

Testing:

• Verified working on AYN Odin 3 (SM8750) using single-channel controls.
• Untested on any other device.

[antnyhills]

Here is a cleaned up and updated pull request. This includes a better layout for the RGB selection and fixes for better reliability.