Add the CLion practice projects

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

untitled2/library.c

@@ -0,0 +1,7 @@
+#include "library.h"
+
+#include <stdio.h>
+
+void hello(void) {
+    printf("Hello, World!\n");
+}