fix(backtest): remove BT-001A exact window restriction now that full data access is available

- 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

app/pages/backtests.py

@@ -830,6 +830,7 @@ def _render_backtests_page(workspace_id: str | None = None) -> None:
                     underlying_units=units,
                     loan_amount=loan,
                     margin_call_ltv=ltv,
+                    data_source=str(data_source_select.value),
                 )
                 # Update cost in saved settings after successful run
                 if str(data_source_select.value) == "databento":

app/pages/settings.py

@@ -119,7 +119,7 @@ def settings_page(workspace_id: str) -> None:
             gold_value=as_positive_float(gold_value.value),
             entry_price=as_positive_float(entry_price.value),
             gold_ounces=as_positive_float(gold_ounces.value),
-            entry_basis_mode=str(entry_basis_mode.value),
+            entry_basis_mode=str(entry_basis_mode.value),  # type: ignore[arg-type]
             loan_amount=parsed_loan_amount,
             margin_threshold=float(margin_threshold.value),
             monthly_budget=float(monthly_budget.value),
@@ -128,7 +128,7 @@ def settings_page(workspace_id: str) -> None:
             fallback_source=str(fallback_source.value),
             refresh_interval=parsed_refresh_interval,
             underlying=str(underlying.value),
-            display_mode=str(display_mode.value),
+            display_mode=str(display_mode.value),  # type: ignore[arg-type]
             volatility_spike=float(vol_alert.value),
             spot_drawdown=float(price_alert.value),
             email_alerts=bool(email_alerts.value),