New query functions in src/data_processing/pathway_queries.py:
- get_drug_market_share: Level 3 drug nodes grouped by directory
- get_pathway_costs: Level 4+ pathway nodes with cost_pp_pa
- get_cost_waterfall: Directorate cost per patient from level 3 aggregation
- get_drug_transitions: Sankey source/target drug transitions with ordinal line labels
- get_dosing_intervals: Parsed average_spacing by trust/directory
- get_drug_directory_matrix: Directory x drug pivot with patient/cost metrics
- get_treatment_durations: Weighted avg_days by drug within directorates
Thin wrappers added in dash_app/data/queries.py for all 7 functions.
Extract load_data() and load_pathway_data() logic from Reflex AppState
into standalone functions in src/data_processing/pathway_queries.py.
Create thin dash_app/data/queries.py wrapper with DB_PATH resolution.