Add Cursor Cloud Docker environment with CI validation

[kapersoft]

Summary

• Adds a .cursor/Dockerfile with PHP 8.5, Composer, and the packages Cursor Cloud needs (openssh-server, sudo, jq) to avoid SSH/sudo setup build failures
• Adds .cursor/environment.json and an idempotent install script for Composer, .env, SQLite, and migrations
• Adds .cursor/test-cloud-environment.sh and a GitHub Actions workflow that builds the image and verifies app install, php-quality hooks, and Pest tests

Test plan

• Confirm the Cloud environment GitHub Actions workflow passes on this PR
• Start a Cursor Cloud Agent from this branch and verify environment setup completes without the Directory nonexistent error
• Delete any saved environment snapshot in Dashboard → Environments if the agent still restores an old image

Made with Cursor