P1 (4/n): unit tests and examples use the level-list constructor

test_shifted_jets, test_shifted_storage, test_raw_exchange and
test_channel_root pass refinements/level_* lists; examples
fixed_patch_jet and fixed_periodic_patch pass refinements=[BOUNDS]
instead of the positional bounds. Assertions kept; the shifted-storage
case base_block-without-fine_block now expects the level-list rule
'blocked refined levels below' (same constraint).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/unit/test_raw_exchange.py

@@ -157,8 +157,9 @@ class RawExchange(unittest.TestCase):
         host = host_module()
         ctx = Mock()
         with self.assertRaisesRegex(ValueError, 'blocked body'):
-            host.FixedPatchStepper(LBMConfig(nx=32, ny=32, viscosity=.1), (4, 4, 28, 28),
-                                   context=ctx, fine_objects=[body(radius=2.15)], observe_raw_exchange=True)
+            host.FixedPatchStepper(LBMConfig(nx=32, ny=32, viscosity=.1), context=ctx,
+                                   refinements=[(4, 4, 28, 28)],
+                                   level_objects=[(), (body(radius=2.15),)], observe_raw_exchange=True)
         ctx.activate.assert_not_called()
 
     def test_all_depth_weights(self):