Enhance UI rendering and add unit tests for simulation functionality

- Updated the `_render` function in `ui.py` to correctly pass the request object to `TemplateResponse`.
- Initialized `upcoming_maintenance` as a typed list in `_load_dashboard` for better type safety.
- Added new unit tests in `test_simulation.py` to cover triangular sampling and uniform distribution defaults.
- Implemented a test to ensure that running the simulation without parameters returns an empty result.
- Created a parameterized test in `test_ui_routes.py` to verify that additional UI routes render the correct templates and context.

tests/unit/test_ui_routes.py

@@ -1,5 +1,6 @@
 from typing import Any, Dict, cast
 
+import pytest
 from fastapi.testclient import TestClient
 
 from models.scenario import Scenario
@@ -98,3 +99,33 @@ def test_dashboard_data_endpoint_returns_aggregates(
     activity_labels = payload["scenario_activity_chart"]["labels"]
     activity_idx = activity_labels.index(scenario.name)
     assert payload["scenario_activity_chart"]["production"][activity_idx] == 800.0
+
+
+@pytest.mark.parametrize(
+    ("path", "template_name"),
+    [
+        ("/", "Dashboard.html"),
+        ("/ui/parameters", "ParameterInput.html"),
+        ("/ui/costs", "costs.html"),
+        ("/ui/consumption", "consumption.html"),
+        ("/ui/production", "production.html"),
+        ("/ui/equipment", "equipment.html"),
+        ("/ui/maintenance", "maintenance.html"),
+        ("/ui/simulations", "simulations.html"),
+    ],
+)
+def test_additional_ui_routes_render_templates(
+    api_client: TestClient,
+    seeded_ui_data: Dict[str, Any],
+    path: str,
+    template_name: str,
+) -> None:
+    response = api_client.get(path)
+    assert response.status_code == 200
+
+    template = getattr(response, "template", None)
+    assert template is not None
+    assert template.name == template_name
+
+    context = cast(Dict[str, Any], getattr(response, "context", {}))
+    assert context