P1 (6/n): exchange-window, raw-exchange, Jet and pinned-remap GPU tests migrated

test_exchange_window, test_raw_exchange_gpu (one fine(block) helper for
the repeated circle+jet construction), test_refinement_jets,
test_multiple_pinned_remap_gpu and test_pinned_body_remap_gpu pass
refinements/level_* lists. Dense fine levels stay level_blocks=[None,
None|block] as before. Assertions unchanged.

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

tests/validation/multigrid/test_exchange_window.py

@@ -25,8 +25,8 @@ EPS = np.finfo(np.float64).eps
 
 
 def build(m, window=True, raw=True):
-    return FixedPatchStepper(config("periodic"), BOUNDS, context=m["context"], base_block=(3, 4),
-                             fine_block=(16, 20), fine_objects=[circle()],
+    return FixedPatchStepper(config("periodic"), context=m["context"], refinements=[BOUNDS],
+                             level_blocks=[(3, 4), (16, 20)], level_objects=[(), (circle(),)],
                              observe_raw_exchange=raw, observe_window_exchange=window)
 
 
@@ -109,10 +109,11 @@ class ExchangeWindowGPU(unittest.TestCase):
         from test_raw_exchange_gpu import BOUNDS as RB, CFG, circle as rc, jet, state
         from CelerisLab.cuda.context import CudaContext
         with CudaContext(0) as ctx:
-            kw = dict(context=ctx, fine_block=(16, 20), fine_objects=[rc()], jets=[jet()],
+            kw = dict(context=ctx, refinements=[RB], level_blocks=[None, (16, 20)],
+                      level_objects=[(), (rc(),)], level_jets=[(), (jet(),)],
                       observe_raw_exchange=True)
-            with FixedPatchStepper(CFG, RB, observe_window_exchange=True, **kw) as windowed, \
-                 FixedPatchStepper(CFG, RB, **kw) as plain:
+            with FixedPatchStepper(CFG, observe_window_exchange=True, **kw) as windowed, \
+                 FixedPatchStepper(CFG, **kw) as plain:
                 arrays = [state(level.shape) for level in windowed._levels]
                 windowed.initialize(*arrays)
                 plain.initialize(*arrays)
@@ -200,11 +201,11 @@ class ExchangeWindowShiftedMRTGPU(unittest.TestCase):
         from CelerisLab.cuda.context import CudaContext
         cfg = LBMConfig(nx=32, ny=24, viscosity=.1, collision="MRT", ddf_shifting=True)
         with CudaContext(0) as ctx:
-            kw = dict(context=ctx, base_block=(12, 8), fine_block=(16, 20), fine_objects=[rc()],
-                      observe_raw_exchange=True)
-            with FixedPatchStepper(cfg, RB, observe_window_exchange=True, **kw) as windowed, \
-                 FixedPatchStepper(cfg, RB, observe_window_exchange=True, **kw) as split, \
-                 FixedPatchStepper(cfg, RB, **kw) as plain:
+            kw = dict(context=ctx, refinements=[RB], level_blocks=[(12, 8), (16, 20)],
+                      level_objects=[(), (rc(),)], observe_raw_exchange=True)
+            with FixedPatchStepper(cfg, observe_window_exchange=True, **kw) as windowed, \
+                 FixedPatchStepper(cfg, observe_window_exchange=True, **kw) as split, \
+                 FixedPatchStepper(cfg, **kw) as plain:
                 arrays = [state(level.shape) for level in windowed._levels]
                 for run in (windowed, split, plain):
                     run.initialize(*arrays)