[FEAT] Byte units should always be shown as integers

[Equationzhao]

Discussed in #234

^{Originally posted by sergeevabc May 9, 2025}
Windows 7 x64, g 0.30.0

$ du -b *
889     gsr1.crt
525     r4.crt
657     we2.crt

$ g -1 --size
889.0 B gsr1.crt
525.0 B r4.crt
657.0 B we2.crt

Why is 0 needed here? How can it be, say, 657.2 B? I guess not.
And to get a more intelligible look, you need to spend effort lengthening the command.

$ g -1 --size --size-unit b
889 B gsr1.crt
525 B r4.crt
657 B we2.crt