feat: Enhance dashboard metrics and summary statistics

- Added new summary fields: variance, 5th percentile, 95th percentile, VaR (95%), and expected shortfall (95%) to the dashboard.
- Updated the display logic for summary metrics to handle non-finite values gracefully.
- Modified the chart rendering to include additional percentile points and tail risk metrics in tooltips.

test: Introduce unit tests for consumption, costs, and other modules

- Created a comprehensive test suite for consumption, costs, equipment, maintenance, production, reporting, and simulation modules.
- Implemented fixtures for database setup and teardown using an in-memory SQLite database for isolated testing.
- Added tests for creating, listing, and validating various entities, ensuring proper error handling and response validation.

refactor: Consolidate parameter tests and remove deprecated files

- Merged parameter-related tests into a new test file for better organization and clarity.
- Removed the old parameter test file that was no longer in use.
- Improved test coverage for parameter creation, listing, and validation scenarios.

fix: Ensure proper validation and error handling in API endpoints

- Added validation to reject negative amounts in consumption and production records.
- Implemented checks to prevent duplicate scenario creation and ensure proper error messages are returned.
- Enhanced reporting endpoint tests to validate input formats and expected outputs.

tests/unit/test_costs.py

@@ -1,8 +1,9 @@
-from fastapi.testclient import TestClient
-from main import app
-from config.database import Base, engine
+from uuid import uuid4
 
-# Setup and teardown
+from fastapi.testclient import TestClient
+
+from config.database import Base, engine
+from main import app
 
 
 def setup_module(module):
@@ -16,43 +17,89 @@ def teardown_module(module):
 client = TestClient(app)
 
 
-def test_create_and_list_capex_and_opex():
-    # Create a scenario to attach costs
-    resp = client.post(
-        "/api/scenarios/", json={"name": "CostScenario", "description": "cost scenario"}
-    )
-    assert resp.status_code == 200
-    scenario = resp.json()
-    sid = scenario["id"]
+def _create_scenario() -> int:
+    payload = {
+        "name": f"CostScenario-{uuid4()}",
+        "description": "Cost tracking test scenario",
+    }
+    response = client.post("/api/scenarios/", json=payload)
+    assert response.status_code == 200
+    return response.json()["id"]
 
-    # Create Capex item
-    capex_payload = {"scenario_id": sid,
-                     "amount": 1000.0, "description": "Initial capex"}
+
+def test_create_and_list_capex_and_opex():
+    sid = _create_scenario()
+
+    capex_payload = {
+        "scenario_id": sid,
+        "amount": 1000.0,
+        "description": "Initial capex",
+    }
     resp2 = client.post("/api/costs/capex", json=capex_payload)
     assert resp2.status_code == 200
     capex = resp2.json()
     assert capex["scenario_id"] == sid
     assert capex["amount"] == 1000.0
 
-    # List Capex items
     resp3 = client.get("/api/costs/capex")
     assert resp3.status_code == 200
     data = resp3.json()
     assert any(item["amount"] == 1000.0 and item["scenario_id"]
                == sid for item in data)
 
-    # Create Opex item
-    opex_payload = {"scenario_id": sid, "amount": 500.0,
-                    "description": "Recurring opex"}
+    opex_payload = {
+        "scenario_id": sid,
+        "amount": 500.0,
+        "description": "Recurring opex",
+    }
     resp4 = client.post("/api/costs/opex", json=opex_payload)
     assert resp4.status_code == 200
     opex = resp4.json()
     assert opex["scenario_id"] == sid
     assert opex["amount"] == 500.0
 
-    # List Opex items
     resp5 = client.get("/api/costs/opex")
     assert resp5.status_code == 200
     data_o = resp5.json()
     assert any(item["amount"] == 500.0 and item["scenario_id"]
                == sid for item in data_o)
+
+
+def test_multiple_capex_entries():
+    sid = _create_scenario()
+    amounts = [250.0, 750.0]
+    for amount in amounts:
+        resp = client.post(
+            "/api/costs/capex",
+            json={"scenario_id": sid, "amount": amount,
+                  "description": f"Capex {amount}"},
+        )
+        assert resp.status_code == 200
+
+    resp = client.get("/api/costs/capex")
+    assert resp.status_code == 200
+    data = resp.json()
+    retrieved_amounts = [item["amount"]
+                         for item in data if item["scenario_id"] == sid]
+    for amount in amounts:
+        assert amount in retrieved_amounts
+
+
+def test_multiple_opex_entries():
+    sid = _create_scenario()
+    amounts = [120.0, 340.0]
+    for amount in amounts:
+        resp = client.post(
+            "/api/costs/opex",
+            json={"scenario_id": sid, "amount": amount,
+                  "description": f"Opex {amount}"},
+        )
+        assert resp.status_code == 200
+
+    resp = client.get("/api/costs/opex")
+    assert resp.status_code == 200
+    data = resp.json()
+    retrieved_amounts = [item["amount"]
+                         for item in data if item["scenario_id"] == sid]
+    for amount in amounts:
+        assert amount in retrieved_amounts