fix: replace unsafe fixed-size buffers with dynamic formatting helpers; add util format helpers; centralize log_on_line cleanup

v0/str.h

@@ -0,0 +1,17 @@
+/**
+ * Contains the definition of the String structure, which is a simple representation of a string in C.
+ */
+#ifndef STR_H
+#define STR_H
+
+#include <stddef.h>
+
+/**
+ * A simple string structure that holds a pointer to the character data and its length.
+ */
+typedef struct {
+    char* data;
+    size_t length;
+} String;
+
+#endif