Clarify raw exchange metadata and streamline host tests

src/CelerisLab/lbm/refinement_tables.py

@@ -66,6 +66,11 @@ def blocked_base_tables(patch, layout, order, wall_aware=False, *, composed_kind
             blocked_kind(layout, dense_kind))
 
 
+# Required device columns plus optional actuation; observation arms are uploaded
+# separately only when enabled. body_id/aperture remain host reduction metadata.
+BLOCKED_BOUNDARY_DEVICE_COLUMNS = ("block", "cell", "dir", "q", "fallback", "surface_velocity")
+
+
 @dataclass
 class _BlockedBoundary:
     """One level's stationary BFL data and mutable Jet velocity column."""
@@ -87,10 +92,8 @@ def _prepare_blocked_boundary(boundary, layout, cfg, jets):
         return None
     fluid_idx, dirs, q, body_id, rx, ry, _, fallback = boundary.curved_host
     tables, _ = blocked_link_tables(layout, boundary.flags, fluid_idx, dirs, q, fallback)
-    # Physical row identity excludes body_id: duplicate owners are always wrong.
-    keys = np.column_stack((fluid_idx, dirs))
-    if len(np.unique(keys, axis=0)) != len(keys):
-        raise ValueError("duplicate physical boundary cut-link")
+    # blocked_link_tables/map_cut_links already rejects repeated (fluid_idx, dir),
+    # independently of body_id, and repeated local writers.
     tables.update(body_id=np.asarray(body_id, np.int32), rx=np.asarray(rx, np.float32),
                   ry=np.asarray(ry, np.float32), aperture=np.zeros(len(dirs), bool))
     actuated = bool(jets) or any(o.surface_actuation is not None for o in boundary.objects)