feat(ugc): make models like LU Toolbox does, within CPU and memory budgets

Parity with LU Toolbox's Process Model, Bake Lighting and icon renderer, with
its defaults as the settings' defaults:

- Colors from its LU palette (UgcPalette: LU colors, LDD colors mapped to the
  nearest LU one, unknown ones black), transparent bricks at 58.82% opacity, a
  brick transparent only when all of its materials are.
- Color variation: each brick's material gets its HSV value shifted in a 2.224
  gamma by up to 5% (times the color's own amount), from a random number of
  the model, brick and material, so reprocessing gives the same colors in
  every LOD. Icons get none, and the icon renderer's color corrections.
- LODs 0 and 2 with its distance logic, written as NiLODNode/NiRangeLODData
  like its exports and the game's own brick models, shapes divided at 65535
  vertices along the longest side like divide_mesh.
- Ambient occlusion like its AO-only bake: 64 rays per vertex, distance 5,
  after hidden surface removal, transparent bricks neither baked nor
  occluding, glow colors added.
- Icons from its icon scene: 50 mm lens at 53.4/19.5 degrees, sun of 2.5 at
  21/50.3 degrees with soft shadows, grey world light with occlusion; LOD 0's
  hidden surface removal and occlusion are reused for them.
- Optional ground plane for hidden surface removal; stats.json per model and
  the previous version's previews kept for comparing.

Budgets, applied live on config reload: max_cpu_percent (workers account
their thread CPU time and sleep to stay under it, long renders included),
worker_nice, max_memory_mb (jobs are estimated from their brick count and
wait until they fit), max_model_bricks and pause_hours. /status and the
traffic report show CPU, memory and throttling.

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

dUgcServer/CMakeLists.txt

@@ -5,12 +5,14 @@ set(DUGC_SOURCES
 	"UgcJobs.cpp"
 	"UgcModel.cpp"
 	"UgcModular.cpp"
+	"UgcPalette.cpp"
 	"UgcRender.cpp"
 	"UgcStorage.cpp"
+	"UgcThrottle.cpp"
 )
 
 add_library(dUgc STATIC ${DUGC_SOURCES})
-target_include_directories(dUgc PUBLIC "." "${PROJECT_SOURCE_DIR}/thirdparty/MD5")
+target_include_directories(dUgc PUBLIC "." "${PROJECT_SOURCE_DIR}/thirdparty/MD5" "${PROJECT_SOURCE_DIR}/thirdparty/nlohmann")
 target_link_libraries(dUgc PUBLIC dCommon glm::glm tinyxml2 MD5)
 
 add_executable(UgcServer "UgcServer.cpp" "UgcProcessor.cpp" "UgcCdClient.cpp")
@@ -36,5 +38,5 @@ target_link_libraries(UgcServer ${COMMON_LIBRARIES} dWeb dServer dUgc)
 
 # Rendering is far too slow unoptimized (minutes a model instead of seconds), so it is optimized in every build type
 if(NOT MSVC)
-	set_source_files_properties("UgcRender.cpp" "UgcModel.cpp" PROPERTIES COMPILE_OPTIONS "-O2")
+	set_source_files_properties("UgcRender.cpp" "UgcModel.cpp" "UgcPalette.cpp" PROPERTIES COMPILE_OPTIONS "-O2")
 endif()