rnd(M03): introduce renderer facade seam

Work-Package: M03-RND-FACADE-001
Agent: sindo-main-codex
Tests: facade/focus/coordinate/manifest contracts, renderer dry-run, coordination and documentation gates
Fidelity: focus targets, budgets, queues, caches and visible renderer behavior remain unchanged

src/tools/probe_render_terrain_height.gd

@@ -37,7 +37,12 @@ func _run_async() -> void:
 	var camera := Camera3D.new()
 	camera.current = true
 	world.add_child(camera)
-	world.set("streaming_focus_source_path", NodePath(camera.name))
+	var render_facade := world.get_node_or_null("WorldRenderFacade")
+	if render_facade == null:
+		push_error("TERRAIN_HEIGHT_PROBE: streaming scene has no WorldRenderFacade")
+		quit(1)
+		return
+	render_facade.set("streaming_focus_source_path", NodePath("../%s" % camera.name))
 	world.set("debug_streaming", false)
 	get_root().add_child(world)
 	await process_frame
@@ -54,8 +59,7 @@ func _run_async() -> void:
 			continue
 		var camera_position := _vector3(checkpoint.get("camera", []))
 		camera.global_position = camera_position
-		if world.has_method("refresh_streaming_focus"):
-			world.call("refresh_streaming_focus", true)
+		render_facade.call("refresh_streaming_focus", true)
 		await create_timer(maxf(0.1, wait_seconds)).timeout
 		var terrain_sample := _sample_terrain(world, camera_position)
 		terrain_sample["name"] = checkpoint.get("name", "checkpoint")