[idd] project: organize source layout

Move cadence and pipeline declarations under capture, and move local
named-pipe handling under ipc.

Flatten display contexts and rename files after their contained classes.
Keep transport headers limited to transport contracts and capabilities.

Consolidate CSwapChainProcessor definitions so each source file matches
the class it implements.

idd/LGIdd/capture/CSwapChainProcessor.h

@@ -56,7 +56,7 @@ private:
   HANDLE                           m_newFrameEvent;
 
   CInteropResourcePool             m_resPool;
-  CPostProcessor                   m_postProcessors[TRANSPORT_FRAME_QUEUE_LENGTH];
+  CPostProcessor                   m_postProcessors[CAPTURE_PIPELINE_SLOTS];
   std::unique_ptr<CFrameProcessor> m_frameProcessor;
   // Reconfiguration is exclusive while per-candidate recording is shared.
   SRWLOCK                          m_pipelineLock = SRWLOCK_INIT;