feat(app): add system tray functionality

[dongfengweixiao]

• Update pubspec.yaml with tray_manager dependency.
• Initialize system tray in app.dart and handle menu item clicks.

Ref #793

[Feichtmeier]

Hey again 👋
Added three change requests/helps

I noticed two things also:

• on linux the dialog pops up and if you do so the app is successfully put into tray and still running and reacting to gnome shell play/pause, however clicking the icon does not return the app to visible mode
• on macos it didnt work at all :( the app just closed, but we could also just add this only for linux and I can try to make it work for macos and windows after your PR (no ETA), that would mean instead of checking for !isMobile you check for Platform.isLinux

[dongfengweixiao]

Hey again 👋 Added three change requests/helps

I noticed two things also:

* on linux the dialog pops up and if you do so the app is successfully put into tray and still running and reacting to gnome shell play/pause, however clicking the icon does not return the app to visible mode

* on macos it didnt work at all :( the app just closed, but we could also just add this only for linux and I can try to make it work for macos and windows after your PR (no ETA), that would mean instead of checking for !isMobile you check for Platform.isLinux

I checked other apps using the tray_manager library, and none of them can open a window by clicking on the icon in Linux. Some programs have conditions in their code to show/hide the window if the system is Windows, otherwise, they display a popup menu. As for the behavior on macOS, I cannot verify it because I don't have the corresponding environment.

[Feichtmeier]

Hey again 👋 Added three change requests/helps
I noticed two things also:

* on linux the dialog pops up and if you do so the app is successfully put into tray and still running and reacting to gnome shell play/pause, however clicking the icon does not return the app to visible mode

* on macos it didnt work at all :( the app just closed, but we could also just add this only for linux and I can try to make it work for macos and windows after your PR (no ETA), that would mean instead of checking for !isMobile you check for Platform.isLinux

I checked other apps using the tray_manager library, and none of them can open a window by clicking on the icon in Linux. Some programs have conditions in their code to show/hide the window if the system is Windows, otherwise, they display a popup menu. As for the behavior on macOS, I cannot verify it because I don't have the corresponding environment.

it doesnt need to be the icon but if the icon with a minimized app would show a menu and one of the menu items is "show window"->click->shows window this would be enough (like in discord/telegram etc)

[dongfengweixiao]

Hey again 👋 Added three change requests/helps
I noticed two things also:

* on linux the dialog pops up and if you do so the app is successfully put into tray and still running and reacting to gnome shell play/pause, however clicking the icon does not return the app to visible mode

* on macos it didnt work at all :( the app just closed, but we could also just add this only for linux and I can try to make it work for macos and windows after your PR (no ETA), that would mean instead of checking for !isMobile you check for Platform.isLinux

I checked other apps using the tray_manager library, and none of them can open a window by clicking on the icon in Linux. Some programs have conditions in their code to show/hide the window if the system is Windows, otherwise, they display a popup menu. As for the behavior on macOS, I cannot verify it because I don't have the corresponding environment.

it doesnt need to be the icon but if the icon with a minimized app would show a menu and one of the menu items is "show window"->click->shows window this would be enough (like in discord/telegram etc)

Clicking the icon to show/hide the window seems to be possible in Linux for qt programs, but not for gtk3 programs.

[Feichtmeier]

hey, was said on discord, sorry for the wrong direction, it needs to be like in the example of the package and the musicpod state class needs with TrayListener

I only added !isMobile checks and the di.reset() ontop

[Feichtmeier]

lets keep it for linux for now so we can test it with the next snap edge release. I got fixed ready which will be pushed then this will be merged and we can test it on linux in the snap edge