feat(ugc): opt-in metal and glow shader groups in made models

Player models are multishader (RenderComponent shader 100): the client
wraps each NiLODNode and draws it with the mapShaders id in its name.
With shader_metal, shader_brushed or shader_glow set, the opaque bricks
are split by look into S<id>_Metal_Model, S<id>_Brushed_Model and
S<id>_Glow_Model beside S01_Opaque_Model and S01_Alpha_Model, each with
every LOD level. Metal is LU Toolbox's metallic colors plus Materials.xml
types (shinySteel; brushedSteel and matteSteel for brushed), glow its
glow colors. Glow shapes get an emissive material (glow_emissive) and
their plain color, not the baked one. Transparent glow stays in S01_Alpha.

All off by default, which writes the same bytes as before (tested). Not
how live looked; models already made change only when made again.

The icon renderer reads the groups back by tag and draws glow at its
plain color and metal with a tinted reflection and highlight.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dUgcServer/UgcFormats.h

@@ -40,12 +40,16 @@ namespace UgcFormats {
 		std::string name; // S01_Opaque_Model: the NiLODNode and its shapes
 		bool transparent{};
 		std::vector<NifLod> lods;
+		// NiMaterialProperty's emissive color (grey) of the group's shapes; 0 the shared white material with none.
+		// The client's emissive shader (S46) lerps from the lit color to the vertex color by vertex alpha times its red.
+		float emissive{};
 	};
 
 	/**
 	 * The layout LU Toolbox exports (setup_lod_data) and the game's own brick models (res/BrickModels/ndmade) have:
 	 * the root node, an NiLODNode per group with NiRangeLODData holding each level's distances, a node per level and
-	 * the level's shapes under it, named like the group. Properties as WriteNif.
+	 * the level's shapes under it, named like the group. Properties as WriteNif; a group with
+	 * an emissive color gets a material of its own.
 	 */
 	std::string WriteLodNif(const std::string& rootName, const std::vector<NifLodGroup>& groups);