Fix: defer window visibility until initialization completes

[aa11653]

Hi rharish101, thank you for developing such a nice DM!

ReGreet currently maps its application window before the asynchronous component initialization has completed. This can briefly expose an unstyled window before the background and custom CSS are applied.

The fixing is quite straight forward. Disable Relm4's automatic visibility-on-activate behavior and show the window explicitly after initialization. The intented focus on login button is maintained through this bug fix.

Tested with:

• demo mode
• custom CSS
• Hyprland (0.55.4-1) + greetd (0.10.3-2) on Arch Linux (kernel 6.18.38-1-lts)

I just replace the /usr/bin/regreet executable and it works well on fresh reboot.

Demo

Before	After

|

Reproduce

Run the following command with the minimal configuration on commit b9bc613 (main) -> afff903 (zzh/fix-unstyled-flashing)

path/to/regreet --demo \
  --config ./etc/greetd/regreet.toml \
  --style ./etc/greetd/regreet.css \
  --logs /tmp/regreet-demo.log

etc.tar.gz

[Cryoniq]

Thank you!

@rharish101 I think #45 might be finally fixed. I built ReGreet with these changes and there are no flickers and it even applies GTK theme correctly. Everything seem to work perfectly.
Just in case - i also removed any extra window rules and other things mentioned in that issue discussion.
Tested with the default recommended niri config from the README.md.

regret_test_pr.mp4

[rharish101]

Thanks a lot for the fix @aa11653! And thanks for testing @Cryoniq!