fix: add missing jack include and remove duplicate compile rule

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

makefile

@@ -54,7 +54,6 @@ transport.o: transport.c transport.h
 
 dispatcher.o: dispatcher.c dispatcher.h
 	$(CC) $(CFLAGS) -c -o $@ $<
-	$(CC) $(CFLAGS) -c -o $@ $<
 
 test_engine.o: test_engine.c engine.h transport.h
 	$(CC) $(CFLAGS) -c -o $@ $<

stress_test.c

@@ -8,6 +8,7 @@
 #include <pthread.h>
 #include "dispatcher.h"
 #include "transport.h"
+#include <jack/jack.h>
 
 static volatile int keep_running = 1;