The backtest engine uses a fixture provider (synthetic_v1) regardless of
the data_source used for price fetching. We must use the fixture provider's
ID for the scenario, not the data source's ID.
This fixes 'Unsupported provider/pricing combination' error when running
backtests with data_source='databento'.
- Pass data_source to derive_entry_spot in backtests.py
- Remove default 'synthetic' value for data_source in derive_entry_spot and validate_preview_inputs
- Update all tests to explicitly pass data_source parameter
- Improve error message with helpful suggestion for Databento/Yahoo Finance
- Change WindowPolicy from EXACT to BOUNDED for backtest fixture
- Pass data_source to run_read_only_scenario so real data can be used
- Fix injected provider identity preservation in BacktestPageService
- Add type: ignore for BacktestHistoricalProvider protocol assignment
- Revert TypedDict change to avoid cascading type issues in pages/
- Update tests to reflect new BOUNDED policy behavior
- Fix return type annotation for get_default_premium_for_product
- Add type narrowing for Weight|Money union using _as_money helper
- Add isinstance checks before float() calls for object types
- Add type guard for Decimal.exponent comparison
- Use _unit_typed and _currency_typed properties for type narrowing
- Cast option_type to OptionType Literal after validation
- Fix provider type hierarchy in backtesting services
- Add types-requests to dev dependencies
- Remove '|| true' from CI type-check job
All 36 mypy errors resolved across 15 files.
