Fix: screen dimming during idle/lock problems

[versenilvis]

Related #29

What changed?

• Skip saving brightness if value is <= 5% and save file already exists (prevents overwriting correct value with screen-off state)
• Add 1.5s cooldown after listener triggers to prevent immediate resume from lockscreen activity, defer reset if activity occurs during cooldown
• Skip idle listener triggers when MprisController.isPlaying is true
• Reset elapsed idle time while media plays
• Prevents screen dimming/lock while watching Youtube, Spotify, etc.

Important

• Didn't test on multi monitors because I don't have
• Need test on multi monitors
• I have caculated to set interval: 1500, it is enough for lock screen to fully load, I tested on 500ms, it will return default brightness immediately after the screen locked. If it is more than 1.5s, we will see a small delay to return default brightness after moving our mouse. It means, after the screen is locked and the screen is at 0% brightness, if we press keyboard, it willl return your default brightness, but it needs a small delay to return after moving out mouse, this will make a really bad user experience

Note

Tested on Zen (Firefox based), tested on Brave (Chromium based) with Youtube
This PR is from latest commit of upstream dev branch ae54c8e

[versenilvis]

my config

[versenilvis]

wait I found a really bad performance behavior when turn on after suspend

[versenilvis]

wait I found a really bad performance behavior when turn on after suspend

this is not from my pull request, some latest commits from upstream dev branch causing this bad performance when turn on PC after suspend