Use ls-style permission strings

[CatsDeservePets]

• Fixes Go's FileInfo implementation causes unexpected and mis-aligned permissions #2264

Tested using the following config:

set info custom:perm

cmd on-load &{{
    cmds=""
    for file in "$@"; do
        perm=$(stat -Lf '%Sp' "$file")
        cmds="${cmds}addcustominfo \"${file}\" $perm; "
    done
    lf -remote "send $id :$cmds"
}}

before	after