feat: Enhance currency handling and validation across scenarios

- Updated form template to prefill currency input with default value and added help text for clarity.
- Modified integration tests to assert more descriptive error messages for invalid currency codes.
- Introduced new tests for currency normalization and validation in various scenarios, including imports and exports.
- Added comprehensive tests for pricing calculations, ensuring defaults are respected and overrides function correctly.
- Implemented unit tests for pricing settings repository, ensuring CRUD operations and default settings are handled properly.
- Enhanced scenario pricing evaluation tests to validate currency handling and metadata defaults.
- Added simulation tests to ensure Monte Carlo runs are accurate and handle various distribution scenarios.

models/__init__.py

@@ -11,6 +11,11 @@ from .metadata import (
     StochasticVariable,
     StochasticVariableDescriptor,
 )
+from .pricing_settings import (
+    PricingImpuritySettings,
+    PricingMetalSettings,
+    PricingSettings,
+)
 from .project import MiningOperationType, Project
 from .scenario import Scenario, ScenarioStatus
 from .simulation_parameter import DistributionType, SimulationParameter
@@ -21,6 +26,9 @@ __all__ = [
     "FinancialInput",
     "MiningOperationType",
     "Project",
+    "PricingSettings",
+    "PricingMetalSettings",
+    "PricingImpuritySettings",
     "Scenario",
     "ScenarioStatus",
     "DistributionType",