test: restore into the same body scene; V3 mock asserts current=False

The checkpoint loader requires matching body count and geometry, so the
round-trip test rebuilds the three-circle scene before loading instead of
an empty simulation (loader unchanged). run_case.main now calls
verify_source(..., current=False); the two dry-run/run mock assertions
follow.

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

tests/integration/test_checkpoint_bodies_gpu.py

@@ -1,6 +1,6 @@
 """Checkpoint save -> load round trip for a scene with passive bodies. Requires GPU.
 
-A fresh Simulation restored from the checkpoint must hold the same populations,
+A fresh Simulation with the same scene, restored from the checkpoint must hold the same populations,
 flags, body count and step count, and must stay bitwise identical to the original
 after both continue for the same number of steps. Checkpoints with Jets are
 refused (documented limitation) and are not covered here.
@@ -36,8 +36,8 @@ class CheckpointBodiesGPU(unittest.TestCase):
         restored = None
         try:
             saved = sim.save_checkpoint(path)
-            restored = make_sim()
-            restored.initialize()
+            # The loader requires the same body count and geometry: rebuild the scene.
+            restored = scene()
             restored.load_checkpoint(saved)
 
             self.assertEqual(restored.bodies.count, len(CIRCLES))

tests/validation/taylor_green/test_projected_pairs.py

@@ -361,7 +361,7 @@ class ProjectedPairsTests(unittest.TestCase):
                  patch.object(run_case, "runtime_identity", side_effect=AssertionError("CUDA reached")), \
                  redirect_stdout(stdout):
                 self.assertEqual(run_case.main(), 0)
-            verify.assert_called_once_with(REPO, MOCK_REVISION)
+            verify.assert_called_once_with(REPO, MOCK_REVISION, current=False)
             self.assertTrue(json.loads(stdout.getvalue())["dry_run"])
             self.assertFalse(output.exists())
 
@@ -454,7 +454,7 @@ class ProjectedPairsTests(unittest.TestCase):
                     else:
                         self.assertEqual(run_case.main(), 0)
                 receipt = json.loads(output.read_text())
-                verify.assert_called_once_with(REPO, MOCK_REVISION)
+                verify.assert_called_once_with(REPO, MOCK_REVISION, current=False)
                 self.assertEqual(selectors, ["projected_linear" if early else "constant"] if depth == 2 else [])
                 self.assertEqual(receipt["source"], source())
                 self.assertEqual(receipt["runtime_identity"], RUNTIME)