Initial commit: Complete open-source Decal rebuild

All 5 phases of the open-source Decal rebuild:

Phase 1: 14 decompiled .NET projects (Interop.*, Adapter, FileService, DecalUtil)
Phase 2: 10 native DLLs rewritten as C# COM servers with matching GUIDs
  - DecalDat, DHS, SpellFilter, DecalInput, DecalNet, DecalFilters
  - Decal.Core, DecalControls, DecalRender, D3DService
Phase 3: C++ shims for Inject.DLL (D3D9 hooking) and LauncherHook.DLL
Phase 4: DenAgent WinForms tray application
Phase 5: WiX installer and build script

25 C# projects building with 0 errors.
Native C++ projects require VS 2022 + Windows SDK (x86).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Native/InjectModern/CMakeLists.txt

@@ -0,0 +1,45 @@
+cmake_minimum_required(VERSION 3.20)
+project(Inject LANGUAGES CXX)
+
+# Force x86 (32-bit) build
+if(NOT CMAKE_SIZEOF_VOID_P EQUAL 4)
+    message(WARNING "Inject.DLL must be built as x86 (32-bit). Use -A Win32 with Visual Studio generator.")
+endif()
+
+add_library(Inject SHARED
+    Inject.cpp
+    Inject.h
+    Inject.def
+)
+
+target_compile_definitions(Inject PRIVATE
+    WIN32
+    _WINDOWS
+    INJECT_EXPORTS
+    _USRDLL
+    UNICODE
+    _UNICODE
+)
+
+target_link_libraries(Inject PRIVATE
+    d3d9
+    advapi32
+    user32
+    kernel32
+    ole32
+    oleaut32
+)
+
+# MSVC-specific settings
+if(MSVC)
+    target_compile_options(Inject PRIVATE /W3 /GR- /EHsc)
+    set_target_properties(Inject PROPERTIES
+        RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin"
+        MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>DLL"
+    )
+endif()
+
+set_target_properties(Inject PROPERTIES
+    OUTPUT_NAME "Inject"
+    SUFFIX ".DLL"
+)