Add headless regression tests for Phase 4b features

- Implement test for popup anchor behavior in rule-builder menus to ensure consistent anchor positioning during menu transitions.
- Create tests for stage logic, including mode transitions, toolbar visibility, and status bar updates.
- Add terrain drag-painting tests to verify correct block placement behavior and conflict handling.
- Introduce walk waypoint tests to check for arrival conditions and position stability after navigation.

scripts/stage_spawner.gd

@@ -14,6 +14,7 @@ extends RefCounted
 const TERRAIN_UTILS := preload("res://scripts/terrain_utils.gd")
 const PROP_UTILS := preload("res://scripts/prop_utils.gd")
 const PROP_BLOCK := preload("res://scripts/prop_block.gd")
+const PROP_LIBRARY := preload("res://scripts/prop_library.gd")
 const STICKMAN_FACTORY := preload("res://scripts/stickman_factory.gd")
 const TRIGGER_AREA := preload("res://scripts/trigger_area.gd")
 
@@ -36,7 +37,9 @@ const TERRAIN_GRID_SIZE: float = 16.0
 
 var _world: Node2D
 var _registry: Array[Dictionary] = []
-var _stickman_data: Dictionary = {}
+var selected_stickman_path: String = DEFAULT_STICKMAN_PATH
+var selected_prop_id: String = "crate"
+var _stickman_cache: Dictionary = {}
 
 # ---------------------------------------------------------------------------
 # Lifecycle
@@ -44,8 +47,8 @@ var _stickman_data: Dictionary = {}
 
 func _init(world: Node2D) -> void:
 	_world = world
-	_stickman_data = STICKMAN_FACTORY.load_stk(DEFAULT_STICKMAN_PATH)
-	if _stickman_data.is_empty():
+	_stickman_cache[DEFAULT_STICKMAN_PATH] = STICKMAN_FACTORY.load_stk(DEFAULT_STICKMAN_PATH)
+	if (_stickman_cache[DEFAULT_STICKMAN_PATH] as Dictionary).is_empty():
 		push_warning("StageSpawner: failed to load default stickman '%s'." % DEFAULT_STICKMAN_PATH)
 	_build_registry()
 
@@ -72,6 +75,47 @@ func get_spawn_offset(id: String) -> Vector2:
 	return entry.get("spawn_offset", Vector2.ZERO)
 
 
+func get_selected_stickman_path() -> String:
+	return selected_stickman_path
+
+
+func get_selected_prop_id() -> String:
+	return selected_prop_id
+
+
+## True when `id` names a terrain template (ground/ramp/step).
+func is_terrain_id(id: String) -> bool:
+	var entry := _find_entry(id)
+	return String(entry.get("kind", "")) == "terrain"
+
+
+## Local-space AABB of a terrain template's centered polygon (before placement),
+## used to size ghosts and rasterize the terrain-painting occupancy cells.
+## The AABB is computed over the SAME sanitized geometry that `_spawn_terrain`
+## actually places (TerrainUtils.sanitize_points at TERRAIN_GRID_SIZE), so the
+## D1 paint stride matches the real block footprint (e.g. the 200px-wide Ground
+## template sanitizes to a 192px footprint and therefore a 192px stride, which
+## makes horizontal runs tile edge-to-edge with no gaps).
+func get_template_aabb(id: String) -> Rect2:
+	var entry := _find_entry(id)
+	if entry.is_empty() or String(entry.get("kind", "")) != "terrain":
+		return Rect2()
+	var template: PackedVector2Array = entry["points"]
+	if template.is_empty():
+		return Rect2()
+	var center := _points_center(template)
+	var centered := PackedVector2Array()
+	for p: Vector2 in template:
+		centered.append(p - center)
+	var cleaned := TERRAIN_UTILS.sanitize_points(centered, TERRAIN_GRID_SIZE)
+	if cleaned.is_empty():
+		return Rect2()
+	var rect := Rect2(cleaned[0], Vector2.ZERO)
+	for p: Vector2 in cleaned:
+		rect = rect.expand(p)
+	return rect
+
+
 ## Spawn the registry type at `world_position`; returns null + push_warning on
 ## an unknown id.
 func spawn(id: String, world_position: Vector2) -> Node2D:
@@ -167,13 +211,7 @@ func _build_registry() -> void:
 			"spawn_offset": Vector2.ZERO,
 		},
 		{
-			"id": "crate", "label": "Crate", "kind": "prop",
-			"payload": PROP_UTILS.create_box(), "preset": PROP_BLOCK.MaterialPreset.WOOD,
-			"spawn_offset": Vector2.ZERO,
-		},
-		{
-			"id": "ball", "label": "Ball", "kind": "prop",
-			"payload": PROP_UTILS.create_ball(), "preset": PROP_BLOCK.MaterialPreset.RUBBER,
+			"id": "prop", "label": "Prop", "kind": "prop",
 			"spawn_offset": Vector2.ZERO,
 		},
 		{
@@ -214,13 +252,16 @@ func _spawn_terrain(entry: Dictionary, world_position: Vector2) -> TerrainBlock:
 		float(entry.get("width", 2.0))
 	)
 	block.position = world_position
+	block.spawn_id = String(entry.get("id", ""))
 	return block
 
 
 func _spawn_prop(entry: Dictionary, world_position: Vector2) -> PropBlock:
-	var payload: Dictionary = entry["payload"]
-	var preset: int = int(entry.get("preset", PROP_BLOCK.MaterialPreset.WOOD))
-	return PROP_UTILS.spawn_prop(_world, world_position, payload, preset, Vector2.ZERO)
+	var t: Dictionary = PROP_LIBRARY.get_entry(selected_prop_id)
+	if t.is_empty():
+		push_warning("StageSpawner: unknown selected prop '%s'." % selected_prop_id)
+		return null
+	return PROP_UTILS.spawn_prop(_world, world_position, t["payload"], int(t["material_preset"]), Vector2.ZERO)
 
 
 func _spawn_area(world_position: Vector2) -> Node2D:
@@ -232,10 +273,14 @@ func _spawn_area(world_position: Vector2) -> Node2D:
 
 
 func _spawn_stickman(world_position: Vector2) -> StickmanRig:
-	if _stickman_data.is_empty():
-		push_warning("StageSpawner: no stickman data loaded; check '%s'." % DEFAULT_STICKMAN_PATH)
+	var data: Dictionary = _stickman_cache.get(selected_stickman_path, {})
+	if data.is_empty():
+		data = STICKMAN_FACTORY.load_stk(selected_stickman_path)
+		_stickman_cache[selected_stickman_path] = data
+	if data.is_empty():
+		push_warning("StageSpawner: no stickman data for '%s'." % selected_stickman_path)
 		return null
-	var rig: StickmanRig = STICKMAN_FACTORY.spawn_from_data(_stickman_data)
+	var rig: StickmanRig = STICKMAN_FACTORY.spawn_from_data(data)
 	if rig == null:
 		push_warning("StageSpawner: failed to spawn stickman.")
 		return null