docs(CHANGES) note gp-sphinx 0.0.1a16 bump

Author: tony

CHANGES

@@ -37,6 +37,9 @@ _Notes on upcoming releases will be added here_
 
 - Visual improvements to API docs from [gp-sphinx](https://gp-sphinx.git-pull.com)-based Sphinx packages (#53)
 - Bump gp-sphinx docs stack to v0.0.1a8 (#54)
+- Bump gp-sphinx docs stack to v0.0.1a16 — docs site now renders
+  via `gp-furo-theme`, a Tailwind v4 respin of Furo, with
+  `sphinx-vite-builder` handling theme-asset builds (#55)
 
 
 ### CLI