Summary

Adds a reusable WP Submission Readiness workflow for WordPress.org release-candidate checks.

The workflow:

• builds the release zip from release.json
• runs Composer validation, existing PHP quality checks, PHPStan, and browser smoke coverage
• unpacks the release artifact and runs WordPress Plugin Check against the packaged plugin
• runs a repo-local metadata/artifact scan that expects the final WordPress.org identity to be Waypoints with slug/text domain waypoints
• uploads the built package and Plugin Check output as artifacts

Also adds tools/check-wp-submission-readiness.php plus PHPUnit coverage for ready, legacy-slug, and not-production-ready readme cases. The scan is intentionally stricter than normal PR CI and is expected to fail against the current package until the deeper waypoints slug/text-domain rename and production-readiness copy updates are complete.

Validation

• cd plugin/plan-your-day && composer phpunit -- tests/SubmissionReadinessToolTest.php
• php -l plugin/plan-your-day/tools/check-wp-submission-readiness.php
• cd plugin/plan-your-day && composer test
• cd plugin/plan-your-day && composer phpstan
• git diff --cached --check
• cd plugin/plan-your-day && composer build-release
• php tools/check-wp-submission-readiness.php --plugin-dir=. --artifact=/opt/lampp/htdocs/plan-your-day/dist/plan-your-day-0.5.zip --expected-name=Waypoints --expected-slug=waypoints failed with the intended current blockers: old text domain/slug, not-production-ready readme copy, and old artifact top-level directory.
• Control scan with --expected-slug=plan-your-day only failed on the intentional not-production-ready readme copy.