release: prepare 2026.09.03-r1

[soulteary]

Summary

• prepare the immutable 2026.09.03-r1 image release
• consolidate the six project-owned MU-plugin sources under plugins/
• keep their runtime installation paths flat under wp-content/mu-plugins/
• update Dockerfile copies, PHP test imports, contribution guidance, and structural regression coverage
• make CI treat every change under plugins/ as an image change
• refresh the pinned wordpress:7.1.0-php8.5-apache digest after upstream tag drift
• mark documentation and Compose as a pending release candidate while 2026.09.02-r2 remains the verified release

Compatibility

This is a source-tree organization change only for the PHP plugins. Existing document-root volumes continue to receive the same managed MU-plugin filenames through entrypoint reconciliation. The recovery tool-*.php endpoints remain at the repository and WordPress document roots because they are not plugins.

Verification

Locally completed:

• git diff --check
• all tests/test-*.sh checks
• documentation consistency
• MU-plugin metadata and directory policy
• entrypoint reconciliation, including mount-point fallback and interrupted-state recovery

GitHub CI will additionally run PHP lint/tests, actionlint, upstream digest verification, and image smoke tests for amd64, arm64, and arm/v7.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-03T01:06:03.196065Z	03e5bfe	PR opened

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