Summary

• persist dockercompose application service subtype records in parseDockerComposeFile()
• detect database services via isDatabaseImage() and upsert ServiceDatabase by application_id
• add schema support for application-owned service subtypes (application_id, nullable service_id)
• update backup/proxy resolution paths to work for both service-owned and application-owned ServiceDatabase
• add targeted unit tests covering application-path persistence markers

Why

Docker Compose apps deployed through GitHub App (build_pack=dockercompose) were detecting DB images but not persisting ServiceDatabase ownership under the application path, so backup flows could not discover/manage those databases consistently.

Notes

• scoped and localized changes only; existing service-stack behavior is preserved
• local php test execution is not available in this environment (php: command not found)
• demo video will be attached in follow-up per bounty requirement

/claim #7528