Backend Service question_router.py

The Arctic-Text2SQL-R1-7B model is used via the Backend Service question_router.py to generate SQL. The Qwen3 model is used within the Backend Service question_router.py for schema selection and question ranking tasks. The Backend Service question_router.py depends on the Backend Service schema_graph.py for schema graph construction and join discovery. The Backend Service question_router.py depends on the Backend Service query_enhancer.py to extract entities and enhance queries for consolidated SQL generation. The Backend Service question_router.py uses the Backend Service consolidation.py to manage transient consolidated views as part of query execution.