docs: sync docs-site/docs/changelog.md with CHANGELOG.md

`Extended Surfaces` job runs `scripts/check_docs_consistency.py`
which verifies the docs-site changelog mirror matches the
canonical `CHANGELOG.md`. Bring it in sync.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: userFRM

docs-site/docs/changelog.md

@@ -89,6 +89,17 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   cause vendor disconnects. Documented contract: callback must
   return within microseconds.
 
+### tdbe
+
+- `tdbe::right::ParsedRight::from_wire_byte(byte: i32) -> Option<Self>`
+  — `const fn` decoder for the FPSS wire `right` byte (`67` for
+  `'C'`, `80` for `'P'`). Inverse of the existing `as_wire_byte()`.
+  Removes the rationale for downstream tick decoders to re-type the
+  `67` / `80` magic numbers at every trust boundary; round-trip
+  property test confirms `from_wire_byte(self.as_wire_byte().unwrap())
+  == Some(self)` for every variant where the forward direction is
+  defined. Patch bump tdbe 0.12.8 → 0.12.9.
+
 ## [8.0.29] - 2026-05-06
 
 ### Removed