wip(assembler): round S1 -- one Core voxel-size source; per-tile feature lists (islands)

AVoxelWorld::CoreVoxelSizeCm (default 25, 32 voxels/tile) flows through plan, field,
mesher, content, water, atmosphere, edits and collision. Staged-owner BuildHost passes at
20 cm (SurfaceWorld + islands, W1/W8/W16, anchors, BP edits, collision) with a fixed-25cm
negative control; default-size hashes match round 4; Core off stays legacy 12.5 cm.
Reusable BuildWorldAssemblyFeatureTileListV1; wired into FloatingIslands only so far.
256-island stress: tile p95 112.5 -> 2.0 ms, 0 mismatches, dropped-feature control fails.
Content placement measured (no populated cells): island ground search 7.25 ms/cell vs
legacy 0.29 ms -- open. Outside-review evaluation in Round5/REPORT.md.

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

Standalone/Research/WorldAssemblerM3/Round5/results/tile_list_audit.json

@@ -0,0 +1,4 @@
+{
+  "baseline":{"islands":4,"connectors":3,"tiles_built":72,"sampled_tiles":60,"samples":60000,"mean_candidates":2.63333333333,"p95_candidates":6,"list_build_total_ms":0.0396,"list_build_p95_ms":0.0009,"before_p95_ms":0.9189,"after_p95_ms":0.9097,"before_median_ms":0.8644,"after_median_ms":0.501,"exact_mismatches":0,"before_hash":"1ae5da3039bdcbdd","after_hash":"1ae5da3039bdcbdd","negative_control":true},
+  "stress":{"islands":256,"connectors":240,"tiles_built":3280,"sampled_tiles":64,"samples":64000,"mean_candidates":3.13170731707,"p95_candidates":4,"list_build_total_ms":95.1326,"list_build_p95_ms":0.0461,"before_p95_ms":112.458,"after_p95_ms":1.972,"before_median_ms":111.66035,"after_median_ms":1.32645,"exact_mismatches":0,"before_hash":"7b92fa4e8d6acf49","after_hash":"7b92fa4e8d6acf49","negative_control":true}
+}

Standalone/Research/WorldAssemblerM3/Round5/results/tile_list_audit_run_ledger.txt

@@ -0,0 +1 @@
+attempt=1 status=passed elapsed_s=7.54 peak_private_MiB=64.7 exit=