michaelmelanson/panda-os

AI Summary: This issue requests documentation for existing "magic numbers" within the codebase to improve clarity and maintainability. Specifically, it targets the `PRINT_BUFFER_SIZE` constant in `print.rs`, requiring an explanation for its value of 256, and keyboard scan code constants in `keyboard.rs`, which need to reference their corresponding Linux input event codes. The goal is to add comments detailing the purpose, rationale, and any constraints for these values.