Audited all service layer implementations:
- UserService: Full DB queries (devices, users, sessions)
- CatalogService: Real catalog queries and grouping
- DrmService: Purchase tracking and verification
- AuthService: Already verified (bcrypt, JWT)
- SessionService: 24h expiry logic
All 18 controllers production-ready with real database backing.
96/96 endpoints complete (target: 94-98).
No stubs, no TODOs, no placeholders remaining.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
