Define all repository interfaces in port/repository.go:
FileRepo, TagRepo, TagRuleRepo, CategoryRepo, PoolRepo, UserRepo,
SessionRepo, ACLRepo, AuditRepo, MimeRepo, and Transactor.
Add OffsetParams and PoolFileListParams as shared parameter structs.
Define FileStorage interface in port/storage.go with Save, Read,
Delete, Thumbnail, and Preview methods.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
