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>

NewNativeStubs/DecalRender/NOTES.md

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+# DecalRender.DLL
+
+## Origin
+Factored out of the old **Inject.DLL** — the rendering functionality (texture creation,
+font rendering, surface blitting) that previously lived inside Inject was moved into
+this dedicated COM server.
+
+## Binary Facts
+- Size: **108 KB**
+- Type: COM in-process server (DLL)
+- Standard 4 COM exports: `DllCanUnloadNow`, `DllGetClassObject`, `DllRegisterServer`, `DllUnregisterServer`
+
+## Key Imports
+| DLL | Functions |
+|-----|-----------|
+| **Inject.DLL** | `BeginSceneO`, `EndSceneO` |
+| **d3dx9_30.dll** | `D3DXCreateTexture`, `D3DXLoadSurfaceFromMemory`, `D3DXCreateFontW`, and others |
+
+## What It Does
+Provides the 2D rendering layer for Decal's overlay UI — creating textures, loading
+surfaces from memory, and drawing text with DirectX fonts. Inject.DLL hooks the
+Direct3D scene begin/end, and DecalRender plugs into those hooks to draw.
+
+## Reconstruction Notes
+- **LOOK AT:** `Managed/Decal.Interop.Render/` for the COM interface definitions
+  this DLL must implement. That directory contains **19 decompiled C# files**
+  describing every interface, enum, and coclass.
+- **LOOK AT:** The old `Native/Inject/` source for rendering code that was likely
+  moved here. Search for anything that touches `IDirect3DTexture9`, `ID3DXFont`,
+  surface blitting, etc.
+- The interop assembly will define the exact vtable layout the managed side expects.
+  Every COM interface in `Decal.Interop.Render` maps to an interface this DLL exposes.