Implement bounded Binary LLSD codec

README.md

@@ -79,6 +79,11 @@ integer/date byte order, synchronized snapshot-based arrays and maps, and
 bounded parser dispatch. OSD map order is intentionally unspecified at the
 public model boundary; encoders must choose and document any stable ordering
 they require. Untrusted dispatch limits input bytes, nesting depth, decoded
-nodes, and aggregate binary allocation before returning a value.
+nodes, and aggregate binary allocation before returning a value. The native
+Binary LLSD codec covers every reference marker, both accepted headers, exact
+numeric and date byte order, seekable stream overloads, and position-bearing
+errors for malformed or truncated input. Its parser and encoder enforce the
+same byte, depth, node, and allocation bounds; map keys are encoded in sorted
+order to make output stable despite the model's intentionally unordered maps.
 The controlled audit aggregates every expected failure by standardized C#
 member ID and rejects unrelated fixture, assertion, compile, or symbol errors.