adding atoi_superscript and isdigit_superscript

srcs/ft_atoi_superscript.c

@@ -0,0 +1,16 @@
+
+#include "libft.h"
+
+/**
+ * Parses a string of superscript digits into an int.
+ * Returns the integer value, or INT_MAX/INT_MIN on overflow.
+ */
+int ft_atoi_superscript(const char *str)
+{
+    long long result = ft_atoll_superscript(str);
+    if (result > INT_MAX)
+        return INT_MAX;
+    if (result < INT_MIN)
+        return INT_MIN;
+    return (int)result;
+}