Initial commit: Vertical Partition Streaming plugin (UE 5.7)

Bounded vertical route partition / streaming for handcrafted spiral climb maps
(Only Up / Only Climb). Not World Partition, not Level Instances as core arch.

- Z-cell segmentation + optional XY subcells, editor builder + commandlet
- NonDestructive visibility backend + streaming-level backend
- Offline HLOD proxies: MergedMesh / SimplifiedProxy (ProxyLOD)
- Universal Level Instance + Packed Level Actor + HISM support (flatten+merge)
- Vertical-aware runtime streamer (full/preload/HLOD/unload, hysteresis,
  velocity prediction, fall-risk), WP-style debug viz + vp.* console
- Safe-by-default: only static decor streams; sky/lights/gameplay stay persistent

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Source/VerticalPartition/Private/VerticalPartitionSettings.cpp

@@ -0,0 +1,12 @@
+// Copyright IHY. Vertical Partition Streaming plugin.
+#include "VerticalPartitionSettings.h"
+
+UVerticalPartitionDeveloperSettings::UVerticalPartitionDeveloperSettings()
+{
+	// DefaultSettings keeps the struct defaults declared in VerticalPartitionTypes.h.
+}
+
+const UVerticalPartitionDeveloperSettings* UVerticalPartitionDeveloperSettings::Get()
+{
+	return GetDefault<UVerticalPartitionDeveloperSettings>();
+}