feat(tty): 实现发送SIGINT终止信号 (#952)

* 实现SIGINT终止信号传递

* 添加test_sigint测试程序

user/apps/test_sigint/main.c

@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+// 信号处理函数
+void handle_signal(int signal)
+{
+    if (signal == SIGINT)
+    {
+        printf("Caught SIGINT (Ctrl+C). Exiting gracefully...\n");
+        exit(0); // 终止程序
+    }
+}
+
+int main()
+{
+    // 注册信号处理函数
+    signal(SIGINT, handle_signal);
+
+    // 模拟一个长时间运行的进程
+    while (1)
+    {
+        printf("Running... Press Ctrl+C to stop.\n");
+        sleep(5);
+    }
+
+    return 0;
+}