fix: expose command_queue_init for testing by removing static

Co-authored-by: aider (deepseek/deepseek-coder) <aider@aider.chat>

engine.c

@@ -285,7 +285,7 @@ static void process_queued_triggers(Engine *engine, jack_nframes_t nframes) {
 }
 
 // Initialize command queue
-static void command_queue_init(CommandQueue *q) {
+void command_queue_init(CommandQueue *q) {
     atomic_store(&q->write_index, 0);
     atomic_store(&q->read_index, 0);
 }