fix: justfile & nushell - should use absolute path

[ryan4yin]

Error:

› just fe
sudo python3 scripts/darwin_set_proxy.py
launchctl unload /Library/LaunchDaemons/org.nixos.nix-daemon.plist
launchctl load /Library/LaunchDaemons/org.nixos.nix-daemon.plist
sleep 1sec
Error: nu::parser::module_not_found

  × Module not found.
     ╭─[/private/var/folders/b7/prh1plw95dlb6jgnbmkpkltw0000gn/T/just-T1454a/fe:134:5]
 133 │
 134 │ use utils.nu *;
     ·     ────┬───
     ·         ╰── module utils.nu not found
 135 │ darwin-build "fern" default;
     ╰────
  help: module files and their paths must be available before your script is run as parsing occurs before anything is evaluated

error: Recipe `fe` failed with exit code 1