refactor(M03): extract M2 placement grouper

src/tools/verify_m2_placement_transform_resolver.gd

@@ -4,6 +4,7 @@ extends SceneTree
 
 const RESOLVER_SCRIPT := preload("res://src/render/m2/m2_placement_transform_resolver.gd")
 const LOADER_PATH := "res://src/scenes/streaming/streaming_world_loader.gd"
+const GROUPER_PATH := "res://src/render/m2/m2_placement_grouper.gd"
 const WATERFALL_WORLD_YAW_OFFSET := PI * 0.5
 const CLIFFROCK_WORLD_YAW_OFFSET := PI
 
@@ -130,6 +131,7 @@ func _verify_path_normalization_and_scale_clamp(failures: Array[String]) -> void
 
 func _verify_loader_boundary(failures: Array[String]) -> void:
 	var source := _read_text(LOADER_PATH, failures)
+	var grouper_source := _read_text(GROUPER_PATH, failures)
 	_expect_true(
 		source.contains("M2_PLACEMENT_TRANSFORM_RESOLVER_SCRIPT.new()"),
 		"loader composes resolver",
@@ -137,14 +139,26 @@ func _verify_loader_boundary(failures: Array[String]) -> void:
 	)
 	_expect_equal(
 		source.count("_m2_placement_transform_resolver.resolve_basis("),
-		3,
-		"three basis adapters",
+		2,
+		"two direct loader basis adapters",
 		failures
 	)
 	_expect_equal(
 		source.count("_m2_placement_transform_resolver.resolve_origin_offset("),
-		3,
-		"three offset adapters",
+		2,
+		"two direct loader offset adapters",
+		failures
+	)
+	_expect_equal(
+		grouper_source.count("placement_transform_resolver.resolve_basis("),
+		1,
+		"one grouped basis adapter",
+		failures
+	)
+	_expect_equal(
+		grouper_source.count("placement_transform_resolver.resolve_origin_offset("),
+		1,
+		"one grouped offset adapter",
 		failures
 	)
 	_expect_true(