wip(assembler): M2 round 2 -- same-LOD borders watertight for MC/hybrid/DC; LOD0/1 transitions still open

Shared halo + deterministic border-quad ownership + T-junction conformance: 625/625 same-LOD for all three.
LOD 2:1 prototype (collar zipper) fails MC 5 / hybrid 38 / DC 40 cases (corners, overhangs).
Hybrid is bit-identical to MC on a sampled native SurfaceWorld cliff; DC rougher. Standalone only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MmSoF64BbRFmk9C3p1VsBJ

Standalone/Research/WorldAssemblerM2/results/cost.csv

@@ -1,46 +1,46 @@
 piece,method,workers,cell_count,triangles,vertices,mesh_ms_median_3,mesh_hash,collision_proxy_hash,collision_geometry_delta_m
-corner90,MC,1,32768,3192,1598,16.5302,0x3e35202e741326da,0x3e35202e741326da,0
-corner90,MC,8,32768,3192,1598,14.1565,0x3e35202e741326da,0x3e35202e741326da,0
-corner90,MC,16,32768,3192,1598,14.5744,0x3e35202e741326da,0x3e35202e741326da,0
-corner90,Hybrid,1,32768,3196,3473,17.3756,0x1c68ed55a97a2b70,0x1c68ed55a97a2b70,0
-corner90,Hybrid,8,32768,3196,3473,14.7298,0x1c68ed55a97a2b70,0x1c68ed55a97a2b70,0
-corner90,Hybrid,16,32768,3196,3473,15.1832,0x1c68ed55a97a2b70,0x1c68ed55a97a2b70,0
-corner90,DC,1,32768,3196,1875,16.346,0x27eb83e4bcb5d532,0x27eb83e4bcb5d532,0
-corner90,DC,8,32768,3196,1875,13.5541,0x27eb83e4bcb5d532,0x27eb83e4bcb5d532,0
-corner90,DC,16,32768,3196,1875,13.9794,0x27eb83e4bcb5d532,0x27eb83e4bcb5d532,0
-doorway,MC,1,32768,2172,1086,15.0354,0x5091c48df9516232,0x5091c48df9516232,0
-doorway,MC,8,32768,2172,1086,13.7949,0x5091c48df9516232,0x5091c48df9516232,0
-doorway,MC,16,32768,2172,1086,13.9519,0x5091c48df9516232,0x5091c48df9516232,0
-doorway,Hybrid,1,32768,2172,2462,15.8758,0xc70ca49841d4ad46,0xc70ca49841d4ad46,0
-doorway,Hybrid,8,32768,2172,2462,14.137,0xc70ca49841d4ad46,0xc70ca49841d4ad46,0
-doorway,Hybrid,16,32768,2172,2462,14.5053,0xc70ca49841d4ad46,0xc70ca49841d4ad46,0
-doorway,DC,1,32768,2172,1376,15.0068,0x7ec18c54d9af2487,0x7ec18c54d9af2487,0
-doorway,DC,8,32768,2172,1376,13.2934,0x7ec18c54d9af2487,0x7ec18c54d9af2487,0
-doorway,DC,16,32768,2172,1376,13.2488,0x7ec18c54d9af2487,0x7ec18c54d9af2487,0
-riser1m,MC,1,32768,4428,2216,17.6744,0x930603791a29a779,0x930603791a29a779,0
-riser1m,MC,8,32768,4428,2216,15.0862,0x930603791a29a779,0x930603791a29a779,0
-riser1m,MC,16,32768,4428,2216,15.501,0x930603791a29a779,0x930603791a29a779,0
-riser1m,Hybrid,1,32768,4432,4775,19.222,0x7a80c8099ed5e2df,0x7a80c8099ed5e2df,0
-riser1m,Hybrid,8,32768,4432,4775,15.9639,0x7a80c8099ed5e2df,0x7a80c8099ed5e2df,0
-riser1m,Hybrid,16,32768,4432,4775,16.2443,0x7a80c8099ed5e2df,0x7a80c8099ed5e2df,0
-riser1m,DC,1,32768,4432,2559,17.6231,0x7a58ef3dd552662f,0x7a58ef3dd552662f,0
-riser1m,DC,8,32768,4432,2559,15.5117,0x7a58ef3dd552662f,0x7a58ef3dd552662f,0
-riser1m,DC,16,32768,4432,2559,15.5445,0x7a58ef3dd552662f,0x7a58ef3dd552662f,0
-cliff_overhang,MC,1,32768,5036,2520,18.5265,0x1881bd75ddc7e7de,0x1881bd75ddc7e7de,0
-cliff_overhang,MC,8,32768,5036,2520,15.2582,0x1881bd75ddc7e7de,0x1881bd75ddc7e7de,0
-cliff_overhang,MC,16,32768,5036,2520,15.3717,0x1881bd75ddc7e7de,0x1881bd75ddc7e7de,0
-cliff_overhang,Hybrid,1,32768,5040,5412,19.8127,0x985b8497adfe9dec,0x985b8497adfe9dec,0
-cliff_overhang,Hybrid,8,32768,5040,5412,15.9717,0x985b8497adfe9dec,0x985b8497adfe9dec,0
-cliff_overhang,Hybrid,16,32768,5040,5412,16.4467,0x985b8497adfe9dec,0x985b8497adfe9dec,0
-cliff_overhang,DC,1,32768,5040,2892,18.232,0x4723adced541eab2,0x4723adced541eab2,0
-cliff_overhang,DC,8,32768,5040,2892,14.6485,0x4723adced541eab2,0x4723adced541eab2,0
-cliff_overhang,DC,16,32768,5040,2892,14.7275,0x4723adced541eab2,0x4723adced541eab2,0
-organic_cave_chamber,MC,1,32768,2444,1224,13.7729,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
-organic_cave_chamber,MC,8,32768,2444,1224,13.0782,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
-organic_cave_chamber,MC,16,32768,2444,1224,13.3739,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
-organic_cave_chamber,Hybrid,1,32768,2444,1224,14.5881,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
-organic_cave_chamber,Hybrid,8,32768,2444,1224,13.732,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
-organic_cave_chamber,Hybrid,16,32768,2444,1224,14.0734,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
-organic_cave_chamber,DC,1,32768,2448,1226,14.1388,0x317a60749cc26f6a,0x317a60749cc26f6a,0
-organic_cave_chamber,DC,8,32768,2448,1226,12.971,0x317a60749cc26f6a,0x317a60749cc26f6a,0
-organic_cave_chamber,DC,16,32768,2448,1226,13.1444,0x317a60749cc26f6a,0x317a60749cc26f6a,0
+corner90,MC,1,32768,3192,1598,16.3157,0x3e35202e741326da,0x3e35202e741326da,0
+corner90,MC,8,32768,3192,1598,53.6312,0x3e35202e741326da,0x3e35202e741326da,0
+corner90,MC,16,32768,3192,1598,86.3833,0x3e35202e741326da,0x3e35202e741326da,0
+corner90,Hybrid,1,32768,3196,3473,17.5341,0x1c68ed55a97a2b70,0x1c68ed55a97a2b70,0
+corner90,Hybrid,8,32768,3196,3473,54.4508,0x1c68ed55a97a2b70,0x1c68ed55a97a2b70,0
+corner90,Hybrid,16,32768,3196,3473,88.7485,0x1c68ed55a97a2b70,0x1c68ed55a97a2b70,0
+corner90,DC,1,32768,3196,1875,16.4166,0x27eb83e4bcb5d532,0x27eb83e4bcb5d532,0
+corner90,DC,8,32768,3196,1875,50.7349,0x27eb83e4bcb5d532,0x27eb83e4bcb5d532,0
+corner90,DC,16,32768,3196,1875,89.7405,0x27eb83e4bcb5d532,0x27eb83e4bcb5d532,0
+doorway,MC,1,32768,2172,1086,15.0271,0x5091c48df9516232,0x5091c48df9516232,0
+doorway,MC,8,32768,2172,1086,53.9143,0x5091c48df9516232,0x5091c48df9516232,0
+doorway,MC,16,32768,2172,1086,86.9611,0x5091c48df9516232,0x5091c48df9516232,0
+doorway,Hybrid,1,32768,2172,2462,16.808,0xc70ca49841d4ad46,0xc70ca49841d4ad46,0
+doorway,Hybrid,8,32768,2172,2462,51.3028,0xc70ca49841d4ad46,0xc70ca49841d4ad46,0
+doorway,Hybrid,16,32768,2172,2462,90.4899,0xc70ca49841d4ad46,0xc70ca49841d4ad46,0
+doorway,DC,1,32768,2172,1376,14.9295,0x7ec18c54d9af2487,0x7ec18c54d9af2487,0
+doorway,DC,8,32768,2172,1376,50.7911,0x7ec18c54d9af2487,0x7ec18c54d9af2487,0
+doorway,DC,16,32768,2172,1376,89.4764,0x7ec18c54d9af2487,0x7ec18c54d9af2487,0
+riser1m,MC,1,32768,4428,2216,17.0044,0x930603791a29a779,0x930603791a29a779,0
+riser1m,MC,8,32768,4428,2216,55.4369,0x930603791a29a779,0x930603791a29a779,0
+riser1m,MC,16,32768,4428,2216,88.7519,0x930603791a29a779,0x930603791a29a779,0
+riser1m,Hybrid,1,32768,4432,4775,18.335,0x7a80c8099ed5e2df,0x7a80c8099ed5e2df,0
+riser1m,Hybrid,8,32768,4432,4775,54.8397,0x7a80c8099ed5e2df,0x7a80c8099ed5e2df,0
+riser1m,Hybrid,16,32768,4432,4775,89.4327,0x7a80c8099ed5e2df,0x7a80c8099ed5e2df,0
+riser1m,DC,1,32768,4432,2559,17.3764,0x7a58ef3dd552662f,0x7a58ef3dd552662f,0
+riser1m,DC,8,32768,4432,2559,53.7095,0x7a58ef3dd552662f,0x7a58ef3dd552662f,0
+riser1m,DC,16,32768,4432,2559,89.3463,0x7a58ef3dd552662f,0x7a58ef3dd552662f,0
+cliff_overhang,MC,1,32768,5036,2520,17.7295,0x1881bd75ddc7e7de,0x1881bd75ddc7e7de,0
+cliff_overhang,MC,8,32768,5036,2520,54.7049,0x1881bd75ddc7e7de,0x1881bd75ddc7e7de,0
+cliff_overhang,MC,16,32768,5036,2520,88.8038,0x1881bd75ddc7e7de,0x1881bd75ddc7e7de,0
+cliff_overhang,Hybrid,1,32768,5040,5412,20.57,0x985b8497adfe9dec,0x985b8497adfe9dec,0
+cliff_overhang,Hybrid,8,32768,5040,5412,55.3158,0x985b8497adfe9dec,0x985b8497adfe9dec,0
+cliff_overhang,Hybrid,16,32768,5040,5412,92.9896,0x985b8497adfe9dec,0x985b8497adfe9dec,0
+cliff_overhang,DC,1,32768,5040,2892,17.9445,0x4723adced541eab2,0x4723adced541eab2,0
+cliff_overhang,DC,8,32768,5040,2892,53.6535,0x4723adced541eab2,0x4723adced541eab2,0
+cliff_overhang,DC,16,32768,5040,2892,91.0395,0x4723adced541eab2,0x4723adced541eab2,0
+organic_cave_chamber,MC,1,32768,2444,1224,13.1379,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
+organic_cave_chamber,MC,8,32768,2444,1224,53.0874,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
+organic_cave_chamber,MC,16,32768,2444,1224,86.6699,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
+organic_cave_chamber,Hybrid,1,32768,2444,1224,14.9431,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
+organic_cave_chamber,Hybrid,8,32768,2444,1224,55.2694,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
+organic_cave_chamber,Hybrid,16,32768,2444,1224,95.9217,0x50031a0a691ec6f4,0x50031a0a691ec6f4,0
+organic_cave_chamber,DC,1,32768,2448,1226,13.2164,0x317a60749cc26f6a,0x317a60749cc26f6a,0
+organic_cave_chamber,DC,8,32768,2448,1226,52.6061,0x317a60749cc26f6a,0x317a60749cc26f6a,0
+organic_cave_chamber,DC,16,32768,2448,1226,86.348,0x317a60749cc26f6a,0x317a60749cc26f6a,0

Standalone/Research/WorldAssemblerM2/results/lod_cliff_crossing.csv

@@ -0,0 +1,4 @@
+method,phase_x_m,phase_y_m,phase_z_m,contour_expected,unmatched_probes,contour_mean_m,contour_max_m,boundary_edges,nonmanifold_edges,edges_before,nonmanifold_before,transition_triangles,paired_loops,capped_loops,unmatched_loops,transition_surface_max_m,fine_segments,coarse_segments
+MC,0.25,0.1,0.1,true,0,0.11871,0.249977,0,0,78,0,234,1,0,0,0.233333,52,26
+Hybrid,0.25,0.1,0.1,true,0,0.0929318,0.419411,0,0,82,0,246,1,0,0,0.238888,56,26
+DC,0.25,0.1,0.1,true,0,0.0929318,0.419411,0,0,82,0,246,1,0,0,0.238888,56,26

Standalone/Research/WorldAssemblerM2/results/lod_cliff_crossing_unbounded_diagnostic.csv

@@ -0,0 +1,4 @@
+method,phase_x_m,phase_y_m,phase_z_m,contour_expected,unmatched_probes,contour_mean_m,contour_max_m,boundary_edges,nonmanifold_edges,edges_before,nonmanifold_before,transition_triangles,paired_loops,capped_loops,unmatched_loops,transition_surface_max_m,fine_segments,coarse_segments
+MC,0.25,0.1,0.1,true,0,0.11871,0.249977,0,0,78,0,234,1,0,0,0.233333,52,26
+Hybrid,0.25,0.1,0.1,true,0,0.0929318,0.419411,0,0,82,0,246,1,0,0,0.238888,56,26
+DC,0.25,0.1,0.1,true,0,0.0929318,0.419411,0,0,82,0,246,1,0,0,0.238888,56,26

Standalone/Research/WorldAssemblerM2/results/native_surface.csv

@@ -0,0 +1,4 @@
+method,manifest_hash,feature_id,feature_type,grid_cells,cell_size_m,origin_x_m,origin_y_m,origin_z_m,iso_probe_z_m,exactly_same_as_mc,mean_abs_field_residual_m,max_abs_field_residual_m,triangles,vertices,boundary_edges,nonmanifold_edges,hash
+MC,0x8933693d9560ba9f,0x9812c26310b90c9,4,32768,0.25,-172,101,-449.239,-445.239,true,0.212167,16.0068,4496,2345,192,0,0x9d58e0603f1bf9c7
+Hybrid,0x8933693d9560ba9f,0x9812c26310b90c9,4,32768,0.25,-172,101,-449.239,-445.239,true,0.212167,16.0068,4496,2345,192,0,0x9d58e0603f1bf9c7
+DC,0x8933693d9560ba9f,0x9812c26310b90c9,4,32768,0.25,-172,101,-449.239,-445.239,false,4.57272,16.5898,3961,2247,504,74,0xd9a992278ffa1a64