Update WP Codebox ownership namespace

[chubes4]

Summary

• Update canonical repository metadata and docs from chubes4/wp-codebox to Automattic/wp-codebox.
• Rename unpublished internal package imports from @chubes4/wp-codebox-* to @automattic/wp-codebox-*.
• Refresh fixtures and smoke assertions affected by the current package metadata and recorded recipe setup executions.

Testing

• npm run build
• npm run recipe-run-timeout-smoke
• npm run artifact-contract-smoke
• npm run preview-public-url-canonical-smoke
• git diff --check
• npm run check attempted end-to-end; after fixing the package provenance fixture it progressed through the relevant namespace/package checks and then hit a transient ECONNREFUSED in preview-public-url-canonical-smoke, which passed when rerun in isolation.

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (GPT-5.5)
• Used for: Resolving the merge conflict, aligning generated package provenance metadata, updating PR notes, and running local verification. Chris remains responsible for review and merge.