FixedPatchStepper(fine_block=..., fine_objects=[circle]) now accepts
passive stationary circles; any surface actuation is rejected before CUDA
(dense fine path unchanged). prepare_fine_boundary still decides legality
on the dense fine grid; its SoA is mapped by the new array-based storage
adapter blocks.blocked_link_tables (map_cut_links: unique receiver owner
and local writer, row order kept; blocked flags sized nblocks*L), which
PeriodicBlockStepper._static_circles now also uses (single-level legality
builder unchanged). Per fine hop on the same buffer: halo -> existing
BlockCurvedBoundary -> BlockStep(flags, kind). No CUDA changes.
Tests: fixture 76 links / 68 q<.5 and 8 seam writes + 8 seam donors per
decomposed layout (both modes); adapter flags sizing; mocked launch-order
contract; GPU: periodic and slot_reservoir, 8 coarse steps, dense fine
body vs 1x1/2x2/4x2 fine blocks, exact values + NaN masks on masked
downloads and raw final arrays, ACTIVE fluid finite, solid/OUTER NaN.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>