Got most of the new memory architecture roughed out.

src/c/payloads/integer.h

@@ -0,0 +1,27 @@
+/**
+ *  payloads/integer.h
+ *
+ *  An integer.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_payloads_integer_h
+#define __psse_payloads_integer_h
+
+#include <stdint.h>
+
+/**
+ * @brief An integer .
+ *
+ * Integers can in principal store a 128 bit value, but in practice we'll start
+ * promoting them to bignums when they pass the 64 bit barrier. However, that's
+ * in the Lisp layer, not the substrate.
+ */
+struct integer_payload {
+    int128_t value;
+};
+
+
+#endif