feat: add integration test target to Makefile

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

makefile

@@ -5,6 +5,10 @@ LDFLAGS ?= -ljack
 looper: src/main.c
 	$(CC) $(CFLAGS) -o looper src/main.c $(LDFLAGS)
 
-.PHONY: clean
+integration: looper tests/integration.c
+	$(CC) $(CFLAGS) -o integration_test tests/integration.c
+	./integration_test
+
+.PHONY: clean integration
 clean:
-	rm -f looper
+	rm -f looper integration_test