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>

internal/outcome/outcome.go

@@ -295,6 +295,7 @@ func (state *outcomeStateSys) toSystem() error {
 		// optional via enablements
 		&spWaylandOp{},
 		&spX11Op{},
+		spPipeWireOp{},
 		&spPulseOp{},
 		&spDBusOp{},