- Add model parameter to filter displayed pricing items to a single model
- DSPY endpoint accepts ?model=xxx param
- Backward compatible: omitting model returns all items
- generate_formula_from_factors(): auto-generate formula from price_factors array
- get_pricing_display(ppid): return structured human-readable pricing data
- wwwroot/api/get_pricing_display.dspy: API endpoint for frontend consumption
- Supports price_factors display layer (label, unit_price, unit_label)
- Backward compatible: old YAML without pricing_type/price_factors works
- Registered via load_pricing() with ServerEnv
