Fixes #7528

When deploying Docker Compose via GitHub App (dockercompose buildpack), databases were detected by isDatabaseImage() but never registered as ServiceDatabase records — the is_database flag was set then discarded. This meant no backup scheduling was available for Compose-deployed databases.

Changes

Core Fix

• Migration — Added nullable application_id to service_databases, made service_id nullable
• Docker Compose Parser — Application path now creates ServiceDatabase records for detected databases
• ServiceDatabase Model — Added application() relationship + getServer()/getParentResource() helpers

Backup Pipeline

• Updated DatabaseBackupJob to work with both Application and Service parent types
• Updated 3 Livewire backup components for dual-parent support

UI

• Added Database Backups page to Application config
• 2 new Livewire components + 2 Blade views
• Routes for application-scoped backup management

Bonus

• Added coolify.service.subType=database label override for custom database images (community request from issue comments)

14 files changed (5 new, 9 modified) — fully backward compatible.

/claim #7528