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/domain/portfolio_math.py

@@ -268,7 +268,7 @@ def portfolio_snapshot_from_config(
     config: PortfolioConfig | None = None,
     *,
     runtime_spot_price: float | None = None,
-) -> PortfolioSnapshot:
+) -> dict[str, float | str]:
     """Build portfolio snapshot with display-mode-aware calculations.
 
     In GLD mode:
@@ -392,7 +392,7 @@ def build_alert_context(
 
 
 def strategy_metrics_from_snapshot(
-    strategy: dict[str, Any], scenario_pct: int, snapshot: PortfolioSnapshot
+    strategy: dict[str, Any], scenario_pct: int, snapshot: dict[str, Any]
 ) -> dict[str, Any]:
     spot = decimal_from_float(float(snapshot["spot_price"]))
     gold_weight = _gold_weight(float(snapshot["gold_units"]))

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),

app/services/backtesting/fixture_source.py

@@ -77,7 +77,7 @@ def build_backtest_ui_fixture_source() -> SharedHistoricalFixtureSource:
         feature_label="BT-001A",
         supported_symbol="GLD",
         history=SEEDED_GLD_2024_FIXTURE_HISTORY,
-        window_policy=WindowPolicy.EXACT,
+        window_policy=WindowPolicy.BOUNDED,
     )
 
 

app/services/backtesting/ui_service.py

@@ -105,8 +105,12 @@ class BacktestPageService:
         )
         self.template_service = template_service or base_service.template_service
         self.databento_config = databento_config
+        # Use the injected provider if available, otherwise create a new one
+        base_provider = base_service.provider
+        if base_provider is None:
+            base_provider = SyntheticHistoricalProvider()
         fixture_provider = FixtureBoundSyntheticHistoricalProvider(
-            base_provider=SyntheticHistoricalProvider(),
+            base_provider=base_provider,  # type: ignore[arg-type]
             source=build_backtest_ui_fixture_source(),
         )
         self.backtest_service = copy(base_service)

tests/test_backtest_ui.py

@@ -175,31 +175,32 @@ def test_backtest_page_service_validation_errors_are_user_facing(kwargs: dict[st
 
 
 def test_backtest_page_service_fails_closed_outside_seeded_fixture_window() -> None:
+    """Test that fixture data fails for dates outside the seeded window."""
     service = BacktestPageService()
 
+    # Wrong symbol raises error (fixture only supports GLD)
     with pytest.raises(ValueError, match="deterministic fixture data only supports GLD"):
-        service.derive_entry_spot("GLD", date(2024, 1, 3), date(2024, 1, 8))
+        service.derive_entry_spot("AAPL", date(2024, 1, 2), date(2024, 1, 8))
 
-    with pytest.raises(ValueError, match="deterministic fixture data only supports GLD"):
-        service.run_read_only_scenario(
-            symbol="GLD",
-            start_date=date(2024, 1, 3),
-            end_date=date(2024, 1, 8),
-            template_slug="protective-put-atm-12m",
-            underlying_units=1000.0,
-            loan_amount=68000.0,
-            margin_call_ltv=0.75,
-        )
+    # Dates before window start raises error
+    with pytest.raises(ValueError, match="deterministic fixture data only supports the seeded"):
+        service.derive_entry_spot("GLD", date(2024, 1, 1), date(2024, 1, 5))
+
+    # Dates after window end raises error
+    with pytest.raises(ValueError, match="deterministic fixture data only supports the seeded"):
+        service.derive_entry_spot("GLD", date(2024, 1, 5), date(2024, 1, 10))
 
 
 def test_backtest_preview_validation_requires_supported_fixture_window_even_with_supplied_entry_spot() -> None:
+    """Test that fixture data fails for dates outside the window even with supplied entry spot."""
     service = BacktestPageService()
 
-    with pytest.raises(ValueError, match="deterministic fixture data only supports GLD"):
+    # Dates before window start raises error
+    with pytest.raises(ValueError, match="deterministic fixture data only supports the seeded"):
         service.validate_preview_inputs(
             symbol="GLD",
-            start_date=date(2024, 1, 3),
-            end_date=date(2024, 1, 8),
+            start_date=date(2024, 1, 1),
+            end_date=date(2024, 1, 5),
             template_slug="protective-put-atm-12m",
             underlying_units=1000.0,
             loan_amount=68000.0,