wip(unreal): VoxelForgeCore UBT module + asset adapter reproduce the standalone world

Luna, integration round 1 (BuildHost only; owner's project and assets untouched):
- New runtime module VoxelForgeCore: one shim per Standalone/Core/core_sources.txt row
  (sources stay canonical under Standalone/), NoPCH/no unity, manifest check; VoxelForge
  links it (no runtime routing yet). UE link-safety audit: 18 shims, 83,843 symbol lines
  vs 399 Unreal-style names, 0 clashes.
- Adapter (editor commandlet path) turns staged copies of the owner's DA_* assets into
  schema-v1 JSON; with clip_radius=3/max_clip_level=8 it reproduces all four Core hashes
  (0xdb2991c73215af4c, 0x8236c5edd7fc8e4f, 0x4c48fa75a543d58e, 0xbea22e76b34a4dfc) and
  walkability 5,642/5,642 at worker limits 1, 8 and 16.
- Noted: the owner's settings asset says max clip level 6 (standalone used 8); Core uses
  25 cm voxels vs the plugin runtime's 12.5 cm.
Not done yet: AVoxelWorld switch and Core runtime route (round 2).
Docs: CODEMAP, ARCHITECTURE, SHARED_CPP_LIBRARY_PLAN, UNREAL_INTEGRATION_REPORT.

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

VoxelForge.uplugin

@@ -21,6 +21,11 @@
 		}
 	],
 	"Modules": [
+		{
+			"Name": "VoxelForgeCore",
+			"Type": "Runtime",
+			"LoadingPhase": "Default"
+		},
 		{
 			"Name": "VoxelForge",
 			"Type": "Runtime",