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/Public/VerticalPartitionDebugComponent.h

@@ -0,0 +1,31 @@
+// Copyright IHY. Vertical Partition Streaming plugin.
+//
+// World-Partition-style debug: coloured cell boxes, ids, actor counts, problem
+// actor highlights, and an on-screen runtime overlay. Driven by the vp.Debug /
+// vp.DebugDraw / vp.DebugOverlay console variables (and the volume's debug flags).
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Components/ActorComponent.h"
+#include "VerticalPartitionDebugComponent.generated.h"
+
+class UVerticalPartitionRuntimeSubsystem;
+
+UCLASS(ClassGroup=(VerticalPartition), meta=(BlueprintSpawnableComponent))
+class VERTICALPARTITION_API UVerticalPartitionDebugComponent : public UActorComponent
+{
+	GENERATED_BODY()
+
+public:
+	UVerticalPartitionDebugComponent();
+
+	virtual void TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction) override;
+
+	/** 3D coloured cell boxes + ids + counts (the spec's DrawDebugCells). */
+	void DrawDebugCells(UVerticalPartitionRuntimeSubsystem* Sub) const;
+	/** On-screen text block of FVerticalRuntimeStats. */
+	void DrawOverlay(UVerticalPartitionRuntimeSubsystem* Sub) const;
+
+private:
+	UVerticalPartitionRuntimeSubsystem* GetSub() const;
+};