Add configurable input post-processing

[mrcha033]

Summary

• add optional [input_post_processing] settings for pointer sensitivity and scroll inversion
• apply configuration changes immediately to active input emulation, including CLI-triggered updates
• add set-mouse-sensitivity and invert-scrolling CLI commands
• document the settings and cover event transformation and CLI parsing with unit tests

If the new configuration section is omitted, behavior remains unchanged (mouse_sensitivity = 1.0, invert_scroll = false).

Motivation

Pointer speed and scroll direction can feel inconsistent when input crosses operating systems. Receiver-side post-processing lets users compensate without changing the local mouse settings on either machine.

Validation

• cargo fmt --all -- --check
• cargo clippy --workspace --all-targets --all-features --locked -- -D warnings
• cargo test --workspace --all-features --locked
• manually verified macOS-to-Arch/Hyprland pointer sensitivity adjustment

Attribution

This refreshes and supersedes #347 by @NeoTheFox, rebasing the work onto current main and adding runtime propagation, documentation, and tests. The implementation commit retains the original author as a co-author.

[10a5er]

sorry for asking, its already nice work:

do you see a possebility to have a scroll-speed value?

when you use something like sway on a macbook, or other exotic input-device/software combination, you sometimes are forced you use very untraditional values for scroll-speed globally for a trackpad to work, which is fine until two (that i encountered) cases:

1. controlling a computer over vnc
2. lan-mouse

in my case, we are talking about scrolling factor is reduces to 5-10%

i can imagine there are local solutions and that many settings if such a slider would exist could lead to bad scrolling-resolution, but i do think if its not that unrealistic to implement the simple existance of the slider would not hurt anyone. :D