feat(debug): add player model and octree visualization toggles

- Show Player Model: render the main character GLTF in camera-local
  space so it stays visible at any pitch.
- Show Octree: overlay the collision octree as colored line segments,
  one wireframe per spatial cell, colored by depth.
- Octree Max Depth: cap recursion to keep the scene readable.

src/hooks/debug/useDebugVisualsDebug.ts

@@ -0,0 +1,33 @@
+import { useDebugFolder } from "@/hooks/debug/useDebugFolder";
+import { useDebugVisualsStore } from "@/managers/stores/useDebugVisualsStore";
+
+export function useDebugVisualsDebug(): void {
+  useDebugFolder("Debug", (folder) => {
+    const controls = {
+      showPlayerModel: useDebugVisualsStore.getState().showPlayerModel,
+      showOctree: useDebugVisualsStore.getState().showOctree,
+      octreeMaxDepth: useDebugVisualsStore.getState().octreeMaxDepth,
+    };
+
+    folder
+      .add(controls, "showPlayerModel")
+      .name("Show Player Model")
+      .onChange((value: boolean) => {
+        useDebugVisualsStore.getState().setShowPlayerModel(value);
+      });
+
+    folder
+      .add(controls, "showOctree")
+      .name("Show Octree")
+      .onChange((value: boolean) => {
+        useDebugVisualsStore.getState().setShowOctree(value);
+      });
+
+    folder
+      .add(controls, "octreeMaxDepth", 0, 10, 1)
+      .name("Octree Max Depth")
+      .onChange((value: number) => {
+        useDebugVisualsStore.getState().setOctreeMaxDepth(value);
+      });
+  });
+}