fix: remove D3D11 debug layer flag that prevented startup on user machines

DRAGONX_DEBUG was defined unconditionally, causing D3D11CreateDevice() to
request the debug layer via D3D11_CREATE_DEVICE_DEBUG. This layer is only
available on machines with the Windows SDK or Graphics Tools installed,
so the call fails with DXGI_ERROR_SDK_COMPONENT_MISSING on regular user
machines — causing the app to silently exit.

src/platform/dx11_context.cpp

@@ -61,13 +61,8 @@ bool DX11Context::init(SDL_Window* window)
         D3D_FEATURE_LEVEL_10_0,
     };
 
-    UINT createDeviceFlags = 0;
-#ifdef DRAGONX_DEBUG
-    createDeviceFlags |= D3D11_CREATE_DEVICE_DEBUG;
-#endif
-
     // Need BGRA support for DirectComposition
-    createDeviceFlags |= D3D11_CREATE_DEVICE_BGRA_SUPPORT;
+    UINT createDeviceFlags = D3D11_CREATE_DEVICE_BGRA_SUPPORT;
 
     HRESULT hr = D3D11CreateDevice(
         nullptr,                    // Default adapter