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/Inject.def

@@ -0,0 +1,37 @@
+; Inject.def - Module definition for Inject.DLL
+; Matches the exports of the original v2.9.8.3 Inject.DLL
+
+LIBRARY "Inject"
+
+SECTIONS
+    .InjectDll READ WRITE SHARED
+
+EXPORTS
+    ; COM server
+    DllCanUnloadNow         PRIVATE
+    DllGetClassObject       PRIVATE
+    DllRegisterServer       PRIVATE
+    DllUnregisterServer     PRIVATE
+
+    ; D3D9 original function pointers (data exports)
+    BeginSceneO             DATA
+    EndSceneO               DATA
+
+    ; Lifecycle
+    DecalStartup
+    Container_Initialize
+    Container_StartPlugins
+    Container_StopPlugins
+    Container_Terminate
+    Container_Draw
+
+    ; VTable hooking utilities
+    HookVTable
+    UnhookVTable
+    GetVTableEntry
+
+    ; Memory patching
+    PatchMemory
+
+    ; Path mapping
+    InjectMapPath