M8-T01: add meter source identity schema

tests/test_energy_models.py

@@ -105,6 +105,9 @@ def test_energy_tables_exist_after_upgrade(energy_db):
         "energy_contract_version",
         "tibber_price",
         "energy_cost_period",
+        "meter_source",
+        "meter_source_channel",
+        "meter_source_binding",
     }
     for table in expected_tables:
         assert table in table_names, f"{table!r} missing after upgrade to head"
@@ -920,6 +923,7 @@ def test_energy_cost_period_meter_id_nullable(energy_db):
         fetched = session.get(EnergyCostPeriod, period_id)
         assert fetched is not None
         assert fetched.meter_id is None
+        assert fetched.source_binding_id is None
 
 
 def test_energy_cost_period_meter_id_fk_enforced(tmp_path: Path):