wip(assembler): M2 round 1 -- sharp-mesher spike: hybrid MC+DC keeps edges, borders and LOD seams not solved yet

Standalone only. Hybrid/DC cut sharp residual 16.7 -> 6.25 cm and split creases ~100%, organic wall
unchanged under hybrid, +4.4% mesh cost, W1/W8/W16 identical. Gate failed: hybrid open edges on 500/625
tagged tile borders; every method fails LOD0/LOD1 (no transition templates yet). Binaries and OBJ meshes not committed.

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

Standalone/ASSEMBLER_M1_REPORT.md

@@ -805,3 +805,15 @@ New source files: none. Modified source files:
 `Standalone/Source/VoxelForge/Private/VoxelMarchingCubesMesher.cpp`, and
 `Standalone/Source/VoxelForge/Public/VoxelMarchingCubesMesher.h`. Modified BuildHost test tool:
 `Tools/TestVoxelForgeCoreWorldHost.ps1`.
+
+## M2 round 1 — sharp-mesher decision spike
+
+The standalone MC / hybrid / DC comparison found a sharp-quality advantage for hybrid, but no
+candidate passes the complete seam gate: MC closes all same-LOD tile borders, hybrid has open
+edges on all 500 tagged-shape cases, DC fails all 625 same-LOD cases, and all three fail the
+LOD0/LOD1 transition audit. No production mesher is selected; hybrid is the candidate to carry
+into the in-game round 2 after border and transition handling is implemented.
+
+Full methods, phase/error/normal/cost/hash tables, seam results, captures, run ledger, and the
+complete new-file list are in [the M2 report](Research/WorldAssemblerM2/REPORT.md). The matched
+contact sheet is [here](Research/WorldAssemblerM2/results/captures/contact_sheet.jpg).