feat: switch grisu2 float-to-string algorithm to hybrid of xjb & zmij algorithms

NOTICE

@@ -91,3 +91,14 @@ the following terms:
 
   Copyright (c) Arm Limited
   The MIT License (https://opensource.org/licenses/MIT)
+
+* xjb-as: https://github.com/JairusSW/xjb-as
+
+  The ECMAScript-compatible f64/f32 -> string (dtoa/ftoa) implementation in
+  std/assembly/util/xjb.ts is vendored from xjb-as.
+
+  Copyright (c) Jairus Tanaka
+  Apache License, Version 2.0 (https://opensource.org/licenses/Apache-2.0)
+
+  xjb-as is itself derived from xjb (https://github.com/xjb714/xjb) and the
+  Zmij shortest-decimal core (https://github.com/vitaut/zmij).