docs: fix stale milla-jovovich org URLs in website and plugin manifests (#787)

Follow-up to #766 which covers version.py, pyproject.toml, README,
CHANGELOG, and CONTRIBUTING. These 11 files still had the old org
name in URLs:

- website/ (VitePress config + 6 docs pages)
- .claude-plugin/ (plugin.json repository, README marketplace command)
- .codex-plugin/ (plugin.json URLs, README links)

Author name fields are intentionally unchanged.

.codex-plugin/README.md

@@ -35,7 +35,7 @@ codex /init
 1. Clone the MemPalace repository:
 
 ```bash
-git clone https://github.com/milla-jovovich/mempalace.git
+git clone https://github.com/MemPalace/mempalace.git
 cd mempalace
 ```
 
@@ -71,5 +71,5 @@ Set the `MEMPAL_DIR` environment variable to a directory path to automatically r
 
 ## Support
 
-- Repository: https://github.com/milla-jovovich/mempalace
-- Issues: https://github.com/milla-jovovich/mempalace/issues
+- Repository: https://github.com/MemPalace/mempalace
+- Issues: https://github.com/MemPalace/mempalace/issues