feat: add window-cycle-width-back action

[oldirtty]

Summary

Add window-cycle-width-back action.

Motivation

I use width_presets = [0.25, 0.375, 0.5, 0.625, 0.75, 1.0] to resize my windows, instead of incrementing/decrementing a fixed value, that way I can have matching fractions that don't necessarily change by a fixed amount.

Being able to cycle back width presets fits better my usability because then I don't need to hit bind multiple times to achieve the desired size.

Type of Change

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

Related Issue

N/A

Testing

• Run:

just format
just test
just lint

• Tested both tilling modes with multiple windows, including wayland native ones like foot

Manual Coverage

• Tested in a nested Umbriel session
• Tested in a native Umbriel session
• Tested with multiple monitors
• Tested with a scaled output
• Tested with native Wayland applications
• Tested with X11 applications through xwayland-satellite
• Tested with the scrolling layout
• Tested with the dwindle layout

Screenshots / Videos

None

Checklist

• This PR is ready for review, or it is marked as Draft.
• I read and followed the relevant guidance in CONTRIBUTING.md.
• I initialized and updated the SceneFX submodule where required.
• I ran just format, or this PR has no C++ changes.
• I ran the relevant build, test, lint, or verification commands, or explained why they were not run.
• I functionally verified compositor behavior where automated checks are insufficient.
• I self-reviewed the changes.
• I checked for new warnings or errors.
• I updated docs/ and examples/config.toml, or this PR does not change user-facing configuration or behavior.
• I used canonical names for config keys, IPC actions, paths, and identifiers.

Additional Notes

I followed a niri-like approach for action name, let me know if maybe something closer to noctalia's IPC would fit better, like umbriel msg window-cycle-width:[previous|next].