docs: add unified logging system documentation and CI/CD integration (refs #87)

- Update staging workflow to use LOG_LEVEL=DEBUG
- Create docs/LOGGING.md with unified logging documentation
- Delete docs/UX-DEBUGGING.md (replaced by LOGGING.md)
- Update architecture to 9-container (6 app + 3 logging)
- Update CLAUDE.md, README.md, docs/README.md, docs/CLAUDE.md
- Update docs/PLATFORM-SERVICES.md deployment section

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -1,6 +1,6 @@
 # MotoVaultPro
 
-Single-tenant vehicle management application with 5-container architecture (Traefik, Frontend, Backend, PostgreSQL, Redis).
+Single-tenant vehicle management application with 9-container architecture (6 application: Traefik, Frontend, Backend, OCR, PostgreSQL, Redis + 3 logging: Loki, Promtail, Grafana).
 
 ## Files
 
@@ -172,8 +172,8 @@ Issues are the source of truth. See `.ai/workflow-contract.json` for complete wo
 
 ## Architecture Context for AI
 
-### Simplified 5-Container Architecture
-**MotoVaultPro uses a simplified architecture:** A single-tenant application with 5 containers - Traefik, Frontend, Backend, PostgreSQL, and Redis. Application features in `backend/src/features/[name]/` are self-contained modules within the backend service, including the platform feature for vehicle data and VIN decoding.
+### 9-Container Architecture
+**MotoVaultPro uses a unified architecture:** A single-tenant application with 9 containers - 6 application (Traefik, Frontend, Backend, OCR, PostgreSQL, Redis) + 3 logging (Loki, Promtail, Grafana). Application features in `backend/src/features/[name]/` are self-contained modules within the backend service, including the platform feature for vehicle data and VIN decoding. See `docs/LOGGING.md` for unified logging system documentation.
 
 ### Key Principles for AI Understanding
 - **Feature Capsule Organization**: Application features are self-contained modules within the backend