Adjust README header artwork layout

Author: RichardGeorgeDavis

README.md

@@ -1,10 +1,8 @@
 # Codex Workspace
 
-<img src="favicon.png" alt="Codex Workspace favicon" width="64" />
-
-<!-- workspace-hub:cover:start -->
-![Codex Workspace cover](.github/assets/cover-readme-20260321.png)
-<!-- workspace-hub:cover:end -->
+<p align="center">
+  <img src="favicon.png" alt="Codex Workspace favicon" width="128" />
+</p>
 
 Codex Workspace is a local-first workspace structure for managing many standalone repositories on one machine without forcing them into a monorepo.
 
@@ -57,6 +55,10 @@ Codex Workspace addresses that with a practical filesystem-first model:
 - Keep WordPress handling pragmatic.
 - Use lightweight manifests where explicit runtime behaviour helps.
 
+<!-- workspace-hub:cover:start -->
+![Codex Workspace cover](.github/assets/cover-readme-20260321.png)
+<!-- workspace-hub:cover:end -->
+
 ## Core Concepts
 
 ### Filesystem-shaped context