Summary

This PR implements a change to set the video thumbnail as the wallpaper.

Motivation

When you change the wallpaper to one from mpvpaper, the color palette isn't set.
Also, if you pause the wallpaper, the previous wallpaper setting remains.

Type of Change

• Bug fix
• New feature
• Breaking change
• Refactoring
• Build / packaging

Related Issue

#8

Testing

Manual Coverage

• Tested on Niri
• Tested on Hyprland
• Tested on Sway
• Tested on another compositor:
• Tested with different bar positions and density settings
• Tested at different interface scaling values
• Tested with multiple monitors

Screenshots / Videos

Checklist

• This PR is ready for review, or it is marked as Draft.
• I self-reviewed the changes.
• I added or updated translations/en.json, or this PR adds no new user-facing strings.
• I did not edit non-English translation files unless this PR is explicitly for translation tooling, an import/export sync, or a maintainer-requested locale change.

Additional Notes

These are simple changes to how the wallpaper is set; they shouldn't affect normal operation.

And this is mainly intended to set the color palette, since the thumbnail has a lower resolution.