Jets: freeze origins, guard set_body, fine-boundary hit helper

Sector/Tube/Radial store origin as a validated float 2-tuple, so caller
lists/arrays cannot change a registered definition. Simulation.set_body
rejects nonzero motion for bodies with Jet-driven links once initialized
(before initialize the sync-time stationary check applies).
prepare_fine_boundary accepts jets in the same coarse cell-edge frame as
fine objects, records read-only FP64 edge-frame hits (FineBoundary2D
.curved_hits, default None) and rejects empty or overlapping selections
before CUDA. FixedPatchStepper wiring is not included.

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

tests/unit/test_jets.py

@@ -221,3 +221,52 @@ def test_manager_rejects_overlapping_jets_and_moving_bodies(device):
     bodies.jets.append(a)
     with pytest.raises(ValueError, match="stationary"):
         bodies.sync_to_gpu(field)
+
+
+def test_origins_are_frozen_float_pairs():
+    point = [6., 5.]
+    array = np.array([6., 5.])
+    jets = [Jet(Sector(point, 0., .5, 4.), Radial(array)), Jet(Tube(array, 0., 1., 1.), Parallel(0.))]
+    point[0], array[0] = 100., 100.
+    assert jets[0].region.origin == (6., 5.) and jets[0].field.origin == (6., 5.)
+    assert jets[1].region.origin == (6., 5.)
+    assert all(type(v) is float for v in jets[0].region.origin)
+    for bad in ((1., 2., 3.), (1., float("nan"))):
+        with pytest.raises(ValueError):
+            Radial(bad)
+
+
+def test_set_body_rejects_motion_of_jet_driven_body(device):
+    from CelerisLab.simulation import Simulation
+    jet = Jet(Sector(CENTER, 0., .6, 3.), Radial(CENTER, inward=False), "quartic", 2e-3)
+    field, bodies = jet_case(device, [jet])
+    sim = SimpleNamespace(bodies=bodies, field=field, lbm_cfg=field.cfg, _initialized=True)
+    with pytest.raises(ValueError, match="stationary"):
+        Simulation.set_body(sim, 0, omega=.01)
+    assert bodies.get(0).state.omega == 0
+    Simulation.set_body(sim, 0, omega=0.)  # stationary updates stay allowed
+
+
+def test_fine_boundary_keeps_edge_frame_hits_and_checks_jets():
+    from CelerisLab.body.objects import SimObject
+    from CelerisLab.body.geometry.circle import CircleGeometry
+    from CelerisLab.config import LBMConfig
+    from CelerisLab.lbm import refinement
+    cfg = LBMConfig(nx=24, ny=24, viscosity=.05)
+    cfg.validate()
+    patch = refinement.FixedPatch2D.from_config(cfg, (4, 4, 20, 20))
+    C, R = (12.25, 12.25), 2.15  # coarse cell-edge frame, as fine_objects
+    body = SimObject(0, geometry=CircleGeometry(*C, R), center=C, radius=R)
+    plan = refinement.prepare_fine_boundary(cfg, patch, [body])
+    assert plan.curved_hits.shape == (len(plan.curved_host[0]), 2)
+    assert not plan.curved_hits.flags.writeable
+    np.testing.assert_allclose(np.hypot(*(plan.curved_hits - C).T), R, rtol=0, atol=1e-12)
+    jet = Jet(Sector(C, 0., .5, R + .01), Radial(C, inward=False))
+    refinement.prepare_fine_boundary(cfg, patch, [body], jets=[jet])
+    away = Jet(Sector((2., 2.), 0., .1, .5), Parallel(0.))
+    with pytest.raises(ValueError, match="selects no"):
+        refinement.prepare_fine_boundary(cfg, patch, [body], jets=[away])
+    with pytest.raises(ValueError, match="overlaps"):
+        refinement.prepare_fine_boundary(cfg, patch, [body], jets=[jet, jet])
+    with pytest.raises(ValueError, match="need fine boundary objects"):
+        refinement.prepare_fine_boundary(cfg, patch, [], jets=[jet])