fix: critical bugs from deep audit
- Fix copy_files() data loss: implement real copy_file across full stack
(FileWritePort, FileManagementUseCase, stubs, service, repository with
atomic CTE + dedup ref_count increment, batch_operations caller)
- Fix plaintext password in replace_default_admin: hash password via
PasswordHasherPort before User::new()
- Fix CalendarService hardcoded user_id: unify CalendarUseCase trait with
explicit user_id parameter on all methods, remove zombie _for_user
duplicates and hardcoded 'current_user_id', update 20 CalDAV handler
call sites
- Previous session: migrate DedupService to PostgreSQL (storage.blobs),
atomic CTEs with compensation for file/folder repository operations
Dionisio
fac0b5e77b