Questro Recommender Model API (CL-EPIDTN, improved_8)

FastAPI service that scores and re-ranks movie/game candidates for the Questro RAG pipeline. It exposes /recommend, /recommend/rerank, /catalog/add, /genres, and /health on port 7749.

The full catalog (189,753 items) is baked into the artifacts in artifacts_improved8/, so the model never needs to hot-add items at runtime. See RECOMMENDER_API_IMPROVED8_DOCS.md for the API reference and build_full_catalog.py for how the catalog is rebuilt.