Merge branch 'feat/signal-and-futex' of https://gitlab.eduxiji.net/T202410487992577/Hajimi-OS into feat/signal-and-futex

Merge branch 'feat/signal-and-futex' of https://gitlab.eduxiji.net/T202410487992577/Hajimi-OS into feat/signal-and-futex

Now you can choose whether to run initcode or init-for-test by editing `kernel/src/bin.S` and removing/adding the `#`.
For example,
```
initcode:
    #.incbin "./xv6-user/initcode"
    .incbin "./xv6-user/init-for-test"
```
runs init-for-test. If you remove the `#` before ".incbin ./xv6-user/initcode" and add `#` to ".incbin ./xv6-user/init-for-test", OS will run "./xv6-user/initcode"
Adding new initcodes like busybox are also easier.