feat: launch 3d architecture documentation portal

docs/user-tutorial/navigate-the-model.md

@@ -0,0 +1,12 @@
+---
+title: "Navigate the Model"
+description: "Move through the POC model and inspect architecture elements."
+---
+
+# Navigate the model
+
+Use pointer or keyboard controls exposed by the POC to orbit, pan, zoom, and select. The interaction contract will be refined with the browser prototype.
+
+## Visible result
+
+The selected element exposes its name and architecture responsibility.