[idd] project: organize driver sources by responsibility

Group the IDD sources and Visual Studio filters by subsystem.

Split the device and swap-chain implementations into focused units,
rename the context classes, and reduce header coupling.

idd/LGIdd/display/IddCxCompat.h

@@ -0,0 +1,34 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2026 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#pragma once
+
+#include <Windows.h>
+#include <wdf.h>
+#include <IddCx.h>
+
+// IddCx 1.10 HDR/WCG types are only visible when the WDK targets
+// (NTDDI >= 0x0A000005) and the build flags select IddCx 1.10 or newer.
+#if defined(IDDCX_VERSION_MAJOR) && defined(IDDCX_VERSION_MINOR) && \
+  (IDDCX_VERSION_MAJOR > 1 || \
+    (IDDCX_VERSION_MAJOR == 1 && IDDCX_VERSION_MINOR >= 10)) && \
+  NTDDI_VERSION >= 0x0A000005
+  #define HAS_IDDCX_110
+#endif