treewide: include PipeWire op and enforce PulseAudio check

This fully replaces PulseAudio with PipeWire and enforces the PulseAudio check and error message. The pipewire-pulse daemon is handled in the NixOS module.

Closes #26.

Signed-off-by: Ophestra <cat@gensokyo.uk>

test/interactive/hakurei.nix

@@ -15,7 +15,7 @@
         command = "foot";
         enablements = {
           dbus = false;
-          pulse = false;
+          pipewire = false;
         };
       };
     };