feat: bake jajce terrain navigation

tests/jajce_world_scaffold_test.gd

@@ -17,7 +17,7 @@ func _run() -> void:
 	var world: Node3D = load("res://world/jajce/JajceWorld.tscn").instantiate()
 	root.add_child(world)
 	await process_frame
-	for frame in 10:
+	for _frame in 10:
 		await physics_frame
 
 	var terrain = world.get_node("TerrainRoot/Terrain3D")
@@ -27,10 +27,9 @@ func _run() -> void:
 		"Terrain3D should use dedicated Jajce data"
 	)
 	_check(terrain.collision_mode != 0, "Terrain3D collision should be enabled for gameplay")
-	var greybox_ground := world.get_node("NavigationRegion3D/GreyboxGround") as StaticBody3D
 	_check(
-		greybox_ground.collision_layer == 0 and greybox_ground.collision_mask == 0,
-		"GreyboxGround should not provide runtime physics collision"
+		not world.has_node("NavigationRegion3D/GreyboxGround"),
+		"JajceWorld should not keep the temporary greybox navigation ground"
 	)
 	_check(
 		configured_texture_count == 6,
@@ -203,6 +202,10 @@ func _run() -> void:
 		navigation_region.navigation_mesh.get_polygon_count() > 0,
 		"Jajce navigation mesh should contain baked polygons"
 	)
+	_check(
+		navigation_region.navigation_mesh.resource_path == "res://world/jajce/JajceNavigationMesh.tres",
+		"Jajce navigation should use the Terrain3D-derived baked mesh resource"
+	)
 	await _wait_for_navigation_map(navigation_map)
 	NavigationServer3D.map_force_update(navigation_map)
 
@@ -224,6 +227,9 @@ func _run() -> void:
 			_check_path_tracks_terrain(
 				terrain, path, "Jajce navigation path should track Terrain3D height"
 			)
+			_check_path_reaches_destination(
+				path, destination, "Jajce navigation path should reach its requested target"
+			)
 
 	var adapter := ActiveWorldAdapter.new()
 	adapter.pantry_storage = pantry
@@ -330,3 +336,17 @@ func _check_path_tracks_terrain(terrain: Terrain3D, path: PackedVector3Array, me
 				% [message, point, terrain_height]
 			)
 			return
+
+
+func _check_path_reaches_destination(path: PackedVector3Array, destination: Vector3, message: String) -> void:
+	if path.is_empty():
+		return
+
+	var final_point := path[path.size() - 1]
+	var final_xz := Vector2(final_point.x, final_point.z)
+	var destination_xz := Vector2(destination.x, destination.z)
+	if final_xz.distance_to(destination_xz) > 1.5:
+		failures.append(
+			"%s: final path point %s is too far from %s"
+			% [message, final_point, destination]
+		)