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.

tests/test_repositories.py

@@ -13,6 +13,7 @@ from models import (
     FinancialCategory,
     FinancialInput,
     MiningOperationType,
+    PricingSettings,
     Project,
     Scenario,
     ScenarioStatus,
@@ -147,6 +148,30 @@ def test_unit_of_work_commit_and_rollback(engine) -> None:
         projects = ProjectRepository(session).list()
         assert len(projects) == 1
 
+
+def test_unit_of_work_set_project_pricing_settings(engine) -> None:
+    TestingSession = sessionmaker(bind=engine, expire_on_commit=False, future=True)
+    with UnitOfWork(session_factory=TestingSession) as uow:
+        assert uow.projects is not None and uow.pricing_settings is not None
+        project = Project(name="Project Pricing", operation_type=MiningOperationType.OTHER)
+        uow.projects.create(project)
+        pricing_settings = PricingSettings(
+            name="Default Pricing",
+            slug="default",
+            default_currency="usd",
+            default_payable_pct=100.0,
+            moisture_threshold_pct=8.0,
+            moisture_penalty_per_pct=0.0,
+        )
+        uow.pricing_settings.create(pricing_settings)
+        uow.set_project_pricing_settings(project, pricing_settings)
+
+    with TestingSession() as session:
+        repo = ProjectRepository(session)
+        stored = repo.get(1, with_pricing=True)
+        assert stored.pricing_settings is not None
+        assert stored.pricing_settings.slug == "default"
+
     # Rollback path
     with pytest.raises(RuntimeError):
         with UnitOfWork(session_factory=TestingSession) as uow:
@@ -302,6 +327,44 @@ def test_project_repository_filtered_for_export(session: Session) -> None:
     assert results[0].scenarios[0].name == "Alpha Scenario"
 
 
+def test_project_repository_with_pricing_settings(session: Session) -> None:
+    repo = ProjectRepository(session)
+    settings = PricingSettings(
+        name="Contract Core",
+        slug="contract-core",
+        default_currency="usd",
+        default_payable_pct=95.0,
+        moisture_threshold_pct=7.5,
+        moisture_penalty_per_pct=100.0,
+    )
+    project = Project(
+        name="Project Pricing",
+        operation_type=MiningOperationType.OPEN_PIT,
+        pricing_settings=settings,
+    )
+    session.add(project)
+    session.flush()
+
+    fetched = repo.get(project.id, with_pricing=True)
+    assert fetched.pricing_settings is not None
+    assert fetched.pricing_settings.slug == "contract-core"
+    assert fetched.pricing_settings.default_currency == "USD"
+
+    listed = repo.list(with_pricing=True)
+    assert listed[0].pricing_settings is not None
+
+    repo.set_pricing_settings(project, None)
+    session.refresh(project)
+    assert project.pricing_settings is None
+
+    repo.set_pricing_settings(project, settings)
+    session.refresh(project)
+    assert project.pricing_settings is settings
+
+    export_results = repo.filtered_for_export(None, include_pricing=True)
+    assert export_results[0].pricing_settings is not None
+
+
 def test_scenario_repository_filtered_for_export(session: Session) -> None:
     repo = ScenarioRepository(session)