wip(assembler): M1 repair round -- raised block and cliff fixed; native 7x faster than legacy

Luna, M1 repair round: the rectangular raised block and the broken cliff shared one cause,
a type-2 solid AABB in the generated plan; it is now a tapered, terrain-following shelf, and
a negative-control audit catches the old box behaviour; seam classification check passes.
Bound audit 298 boxes / 8,046 samples, 0 misses. Evaluator and 120-tile density/mesh/payload/
topology hashes identical at W1/W8/W16. Cave regression: walkability 5,642/5,642, 64/64 tiles.
Legacy mismatch unchanged (0 biome mismatches, 18.14% signs).
Speed (matched workloads): 120-tile full detail 0.089 s native vs 0.625 s legacy; 529-tile
clipmap 3.858 s vs 11.687 s -- 2.29 s above the ~1.57 s aim; LOD8 dominates (165 unknown
tiles, 13.27 M field calls, 10.88 M column-cache misses).
My capture review: coast matches legacy closely; surface clean but a dark flat slab on the far
horizon; cliff shelf renders as a stack of thin plates with back faces showing (sub-voxel
shelf thickness suspected).

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

Standalone/Research/WorldAssemblerM1/round3/final/audit.txt

@@ -0,0 +1,31 @@
+[ProcessControls] priority_class=Normal priority_source=argument affinity_mask=0xFFFF affinity_source=argument requested_affinity=0xFFFF system_affinity=0xFFFF
+[ColdTimeline] stage=owner_data_load begin_ms=0.044
+[ColdTimeline] stage=owner_data_load end_ms=13.079
+[WorldAssemblerPrototype] recipe_version=1 evaluator_version=3 strata=1 biomes=4 strate_index=1 chunk_z=-16..-79 serialized_bytes=4524 recipe_hash=dbbc0ac1267bbb97 plan_hash=b5f74995825f80c0 manifest_hash=023cfa0da07fc3a6 source=owner_surface_params_and_biome_map route_points=0 features=1
+[WorldAssemblerPlanTiming] total_ms=6.932 status=PASS
+[WorldAssemblerBlock] name=Heightfield2D evaluator=3 reads=biome writes=height,rock influence_xy=global influence_z_q=-647168..-122880 detail_envelope_q=2829824 minimum_feature_q=512 status=PASS
+[WorldAssemblerBoundAudit] boxes=298 point_samples=8046 missed_bounds=0 unknown_bounds=0 border_boxes=16 cliff_boxes=16 cap_boxes=9 negative_coordinate_boxes=250 exception_boxes=1 exception_point_samples=27 deliberately_wrong_bound_detected=true status=PASS
+[WorldAssemblerCliffShapeAudit] top_plane_q=-412358 baseline_air_samples=25 old_type2_blocked=25 tapered_type4_blocked=0 negative_control_detected=true status=PASS
+[WorldAssemblerTileSeamAudit] boxes=50 lattice_samples=900 false_classifications=0 seam_spacing_vox=32 box_span_vox=16 status=PASS
+[WorldAssemblerEvaluatorHash] samples=4096 W1=6d249c9e3b7c7a03 W8=6d249c9e3b7c7a03 W16=6d249c9e3b7c7a03 deterministic=true
+[WorldAssemblerQueryTiming] samples=4096 native_W1_ms=13.934 native_W8_ms=16.318 native_W16_ms=32.236 scope=point_evaluation_only
+[WorldAssemblerSurfaceShapeDiagnostic] samples=4096 owner_voxel_cm=25.0 core_voxel_cm=25.0 mean_owner_height=-1949.169 mean_native_height=-1950.535 mean_offset=-1.366 mae=13.060 mae_after_mean_offset_removal=14.046 max_error=203.728 regression_native_equals_slope_owner_plus_offset_slope=0.95136 offset=-96.174 correlation=0.96496 owner_biome_samples=4096 owner_biome_id_mismatches=0
+[WorldAssemblerCaptureSite] name=surface target_vox=(0,0,-2015.77) owner_ground_vox=-2015.77 native_ground_vox=-2015.78 score=0.00000 camera_m=(0.000,-35.000,-487.943,0,-22)
+[WorldAssemblerCaptureSite] name=biome_border target_vox=(512,-832,-2035.65) owner_ground_vox=-2035.65 native_ground_vox=-2035.64 score=0.50000 camera_m=(128.000,-243.000,-492.912,0,-22)
+[WorldAssemblerCaptureSite] name=coast target_vox=(1344,-128,-1975.02) owner_ground_vox=-1975.02 native_ground_vox=-1975.02 score=0.01904 camera_m=(336.000,-67.000,-477.755,0,-22)
+[WorldAssemblerCaptureSite] name=cliff target_vox=(-672,420,-1846.85) owner_ground_vox=-1846.85 native_ground_vox=-1845.25 score=0.00000 camera_m=(-168.000,70.000,-445.712,0,-22)
+[WorldAssemblerLegacyCompare] samples=4096 mean_abs_density_error=17.2259 max_abs_density_error=392.4136 sign_mismatches=743 legacy_point_queries_ms=62.241 status=MEASURED_NOT_PARITY_GATE
+[GridStairDistanceRepair] exact_endpoint_proxies=0 occupancy_corrections=0
+[ShapeProfile] local_primitives=25.228ms line_bins=3.646ms rock_lines_wall=6.113ms rock_lines_worker=6.113ms candidate_axes_wall=0.721ms candidate_axes_worker=0.721ms candidate_merge_wall=0.019ms candidate_merge_worker=0.019ms candidate_merge_serial=0.008ms detail_lines_wall=0.158ms detail_lines_worker=0.158ms
+[ShapeSubstage] detail_apply=0.161ms sign_edge_distances=0.035ms passage_validation=0.000ms shared_field_primitives=0.027ms far_parents=0.000ms
+[ShapeAllocation] words=0.15MiB candidate_axis_words=0.15MiB proxy=0.63MiB primitives=0.09MiB spatial_bins=24350 spatial_bin_refs=51824 spatial_bin_capacity=98572 inline_bins=24063 overflow_bins=287 far_primitive_build=0.000ms far_bin_rebuild=0.000ms
+[ShapeCompile] primitives=203 rooms=35 tunnels=31 passages=2 nodes=328509 packed=0.15 MiB surface_proxy_nodes=0 proxy_address_capacity=0.63 MiB workers=1
+[ShapeStage] local-shapes=28.898 ms intervals+signs=6.909 ms surface-band=0.196 ms far-parents=0.000 ms total=36.227 ms candidates=0 flips=0 walk=0/0
+[RoomFloorJoinAudit] automatic_room_overlaps=2 thin_positive_support_overlays=0 status=PASS
+[FloorSlopeJoinAudit] raw_unmarked_max_delta=4.43634 vox generated_tangent_delta=0.00000 vox bend_direction_slope_change=0.24018 vox marked_max_delta=0.00000 vox marked_joins=0 threshold=0.750 status=PASS
+[FloorProfileBlend] c1_segments=149 max_curve_deviation=0.993 vox threshold=2.000 status=PASS
+[TunnelRadiusAudit] shared_joins=116 legacy_fixed_segment_max_step=2.4469 vox smoothed_profile_max_step=1.5384 vox tapered_endpoint_max_delta=0.000000 vox radius_slope_join_delta=0.00000000 floor_endpoint_max_delta=0.000000 vox floor_slope_join_delta=0.00000 unmarked_floor_slope_delta=0.00000 marked_floor_slope_delta=0.00000 marked_slope_joins=0 smooth_union_growth_bound=0.2500 vox thresholds=(0.005,0.000001,0.005,0.25) status=PASS
+[TunnelBendAudit] sharpest_bend=39.46 deg centerline=(-97.09,-169.65,-27.50) vox tangent=(0.9188,-0.2614,0.2959) camera_yaw=105.88 camera_pitch=17.21
+[WorldAssemblerCoreQuery] compiled=true compile_ms=36.269 samples=45 max_abs_error=0.00000000 render_meshes_generated=0 readiness=field_ready_without_meshes status=PASS error=none
+[WorldAssemblerCapturePair] resolution=320x200 xy_span_vox=3200 height_range=[-2106.11,-1410.26] owner_columns=64000 owner_saved=true native_saved=true files=owner-reference-height.ppm,native-prototype-height.ppm status=PASS
+[WorldAssemblerFullViewTiming] status=NOT_MEASURED_IN_AUDIT_MODE; capture_viewer_runs_report_separately