feat: add spreading mushroom to playground level

game/scenes/Interaction/mushroom.gd

@@ -0,0 +1,75 @@
+extends Node3D
+
+@export var spread_radius := 2.0
+@export var spread_interval_min := 5.0
+@export var spread_interval_max := 15.0
+@export var max_mushrooms_in_radius := 3
+@export var check_radius := 1.5
+@export var max_total_mushrooms := 50
+
+static var total_mushrooms := 0
+
+@onready var spread_timer: Timer = $SpreadTimer
+@onready var ground_ray: RayCast3D = $GroundRay
+
+func _ready() -> void:
+	total_mushrooms += 1
+	_setup_timer()
+	
+	# Randomize initial scale for variety
+	scale = Vector3.ONE * randf_range(0.8, 1.2)
+	rotation.y = randf_range(0, TAU)
+
+func _setup_timer() -> void:
+	spread_timer.wait_time = randf_range(spread_interval_min, spread_interval_max)
+	spread_timer.start()
+
+func _on_spread_timer_timeout() -> void:
+	if total_mushrooms >= max_total_mushrooms:
+		return
+	
+	if _count_nearby_mushrooms() >= max_mushrooms_in_radius:
+		# Too crowded, try again later
+		_setup_timer()
+		return
+	
+	_attempt_spread()
+	_setup_timer()
+
+func _attempt_spread() -> void:
+	var random_angle := randf_range(0, TAU)
+	var random_dist := randf_range(spread_radius * 0.5, spread_radius)
+	var offset := Vector3(cos(random_angle) * random_dist, 5.0, sin(random_angle) * random_dist)
+	
+	ground_ray.position = offset
+	ground_ray.force_raycast_update()
+	
+	if ground_ray.is_colliding():
+		var collision_point := ground_ray.get_collision_point()
+		var collision_normal := ground_ray.get_collision_normal()
+		
+		# Only spread on relatively flat surfaces
+		if collision_normal.dot(Vector3.UP) > 0.7:
+			_spawn_mushroom(collision_point)
+
+func _spawn_mushroom(pos: Vector3) -> void:
+	var mushroom_scene = load(scene_file_path)
+	var new_mushroom = mushroom_scene.instantiate()
+	get_parent().add_child(new_mushroom)
+	new_mushroom.global_position = pos
+	
+	# Visual feedback/animation
+	new_mushroom.scale = Vector3.ZERO
+	var tween = create_tween()
+	tween.tween_property(new_mushroom, "scale", Vector3.ONE * randf_range(0.8, 1.2), 1.0).set_trans(Tween.TRANS_BACK).set_ease(Tween.EASE_OUT)
+
+func _count_nearby_mushrooms() -> int:
+	var count := 0
+	for mushroom in get_tree().get_nodes_in_group("mushrooms"):
+		if mushroom == self: continue
+		if global_position.distance_to(mushroom.global_position) < check_radius:
+			count += 1
+	return count
+
+func _exit_tree() -> void:
+	total_mushrooms -= 1