feat(input): add touchpad acceleration and sensitivity

[AdityaKr015]

Summary

This PR add the acceleration and sensitivity for touchpad. Flat and Adaptive just like mouse.

Motivation

Without accel and sensitivity setting using touchpad feels so slow.

Type of Change

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

Testing

• Ran just format, just test all clean. just lint shows errors on recent Wine HDR files
• Build the branch and installed it to test natively
• Tried adaptive, flat, with different sensitivity, everything working as expected

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

recording_20260824_120452.mp4

Previous video wasn't good enough
Just using the touchpad of ThinkPad L14 Gen 2

Checklist

• This PR is ready for review.
• I read and followed the relevant guidance in CONTRIBUTING.md.
• I initialized and updated the SceneFX submodule where required.
• I ran just format.
• I ran the relevant build, test, lint, or verification commands.
• 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.
• I used canonical names for config keys, IPC actions, paths, and identifiers.