M8-T16: add thermal meter cost APIs

tests/test_api_energy.py

@@ -304,6 +304,35 @@ def test_prices_no_contract_returns_empty(energy_client):
     assert body["points"] == []
     assert body["tariff"] is None
     assert "currency" in body
+    assert client.get("/api/energy/prices?scope=electricity").json() == body
+
+
+def test_prices_thermal_returns_active_contract_snapshot(energy_client):
+    client, engine, _app = energy_client
+    now = datetime.now(UTC)
+    values = {
+        "variable": {"heating": "20.123456", "hot_water_heating": "4", "hot_water": "2", "hot_water_tax": "1"},
+        "standing": {"heating_network": "0", "metering": "0", "delivery_set": "0", "hot_water_network": "0", "other": "0"},
+    }
+    with Session(engine) as session:
+        contract = EnergyContract(name="thermal", kind="district_heating", scope="thermal", active=True,
+                                  currency="EUR", created_at=now, updated_at=now)
+        session.add(contract)
+        session.flush()
+        session.add(EnergyContractVersion(contract_id=contract.id, effective_from=now - timedelta(days=1),
+                                          values=values, created_at=now))
+        session.commit()
+    _login(client)
+    response = client.get("/api/energy/prices?scope=thermal")
+    assert response.status_code == 200
+    body = response.json()
+    assert body == {
+        "kind": "district_heating", "currency": "EUR", "points": [],
+        "contract_version_id": body["contract_version_id"],
+        "effective_from": body["effective_from"], "values": values,
+    }
+    assert client.get("/api/energy/prices").json()["points"] == []
+    assert client.get("/api/energy/prices?scope=invalid").status_code == 422
 
 
 # ---------------------------------------------------------------------------
@@ -334,6 +363,7 @@ def test_prices_manual_contract_returns_tariff(energy_client):
     assert abs(tariff["sell_dal"] - 0.10) < 1e-6
     # sell_normal = 0.10
     assert abs(tariff["sell_normal"] - 0.10) < 1e-6
+    assert client.get("/api/energy/prices?scope=electricity").json() == body
 
 
 # ---------------------------------------------------------------------------
@@ -369,6 +399,7 @@ def test_prices_tibber_contract_returns_points(energy_client):
         assert abs(p["buy"] - 0.245) < 1e-6
         assert abs(p["sell"] - (0.245 - 0.1108)) < 1e-4
         assert p["level"] == "NORMAL"
+    assert client.get("/api/energy/prices", params={"scope": "electricity", "start": start, "end": end}).json() == body
 
 
 def test_prices_tibber_sell_reflects_sell_fee(energy_client):