* feat: remove nginx and serve Angular directly from Spring Boot
* fix: handle null values in EnabledFields deserialization from persisted JSON
* fix(migration): auto-repair failed Flyway migrations on startup
* fix(migration): replace DB triggers with app-level orphan cleanup
* fix: restore default port to 6060 for backwards compatibility
* fix: align all port references to 6060 and add OPDS compression MIME types
* fix: resolve NG0101 recursive tick error in book browser selection
---------
Co-authored-by: acx10 <acx10@users.noreply.github.com>