feat(simulation): load combined rover collision

src/k1link/simulation/projects.py

@@ -671,6 +671,11 @@ def _world_manifest(project_id: str, artifacts: list[dict[str, Any]]) -> dict[st
         )
         return f"/api/v1/simulation-worlds/projects/{project_id}/artifacts/{encoded}"
 
+    collision_mesh_url = (
+        url_for("rover-collision-mesh")
+        or url_for("rover-terrain-mesh")
+        or url_for("collision-mesh")
+    )
     return {
         "schema_version": WORLD_MANIFEST_SCHEMA,
         "project_id": project_id,
@@ -679,9 +684,8 @@ def _world_manifest(project_id: str, artifacts: list[dict[str, Any]]) -> dict[st
             "streamed_sog_url": url_for("stream-manifest"),
         },
         "collision": {
-            "mesh_url": url_for("rover-terrain-mesh") or url_for("collision-mesh"),
-            "available": (url_for("rover-terrain-mesh") or url_for("collision-mesh"))
-            is not None,
+            "mesh_url": collision_mesh_url,
+            "available": collision_mesh_url is not None,
         },
         "transforms": {
             "world_from_visual": [1, 0, 0, 0, 0, -1, 0, 0, 0, 0, -1, 0, 0, 0, 0, 1],