M8-R08: add atomic meter close and binding transfer

tests/test_energy_cost.py

@@ -2176,6 +2176,31 @@ class TestComputeClosedPeriods:
 
 
 class TestRecomputeRange:
+    def test_strict_mode_propagates_period_failure_without_committing(
+        self, energy_db: Session, monkeypatch: pytest.MonkeyPatch
+    ) -> None:
+        """Lifecycle callers can own one rollback for writes and recompute."""
+        from app.services import energy_cost
+
+        monkeypatch.setattr(
+            energy_cost, "compute_period", lambda *_args, **_kwargs: (_ for _ in ()).throw(RuntimeError("boom"))
+        )
+
+        with pytest.raises(RuntimeError, match="boom"):
+            recompute_range(energy_db, _T0, _T1, commit=False, strict=True)
+
+    def test_default_mode_keeps_best_effort_period_failure(
+        self, energy_db: Session, monkeypatch: pytest.MonkeyPatch
+    ) -> None:
+        """Existing workers retain their tolerant recompute behaviour by default."""
+        from app.services import energy_cost
+
+        monkeypatch.setattr(
+            energy_cost, "compute_period", lambda *_args, **_kwargs: (_ for _ in ()).throw(RuntimeError("boom"))
+        )
+
+        assert recompute_range(energy_db, _T0, _T1, commit=False) == 0
+
     def test_default_commit_is_visible_to_a_new_session(self, energy_db: Session) -> None:
         """The public recompute API retains its standalone commit behaviour."""
         _setup_manual_scenario(energy_db)