Reorganize into role-based folders and consolidate art

Move every script and scene into role-based directories (actors/, systems/, ui/,
levels/, props/) and all raw art under art/ (grouped by role, snake_case,
Extract-Textures GLBs), dropping Blender version-suffix noise. Filenames are
snake_case (PascalCase reserved for class_name) to avoid case-insensitive
filesystem aliasing on the web/macOS targets. Routes the bull's hits through the
typed DamageEvent pipeline and wires the bull's abilities to the Fx library.
Updates CLAUDE.md's folder-layout overview to match.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CCyaJPTHCH9EDthpf4A5Sj

props/barrel_simple.gd

@@ -0,0 +1,41 @@
+extends StaticBody3D
+## A smashable lobby barrel. Joins the &"barrel" group so the HUD can tally how many
+## remain and fire the "cleared the lobby" reward once the last one bursts.
+
+signal destroyed
+
+# Preload the broken barrel scene
+const BARREL_BROKEN_SCENE = preload("res://props/barrel_broken.tscn")
+
+var _destroyed := false
+
+
+func _ready() -> void:
+	add_to_group(&"barrel")
+
+
+func destroy_barrel():
+	# Guard against a double hit in the same frame counting the same barrel twice.
+	if _destroyed:
+		return
+	_destroyed = true
+
+	# 1. Instantiate the broken pieces
+	var broken_instance = BARREL_BROKEN_SCENE.instantiate()
+
+	# 2. Place the fragments exactly where the intact barrel currently is
+	broken_instance.global_transform = self.global_transform
+
+	# 3. Add the fragments to the main game tree
+	get_parent().add_child(broken_instance)
+
+	# 4. (Optional) Apply a physics push to the fragments if you want an explosive effect
+	for child in broken_instance.get_children():
+		if child is RigidBody3D:
+			# Pushes pieces slightly outward and upward
+			var random_direction = Vector3(randf_range(-1, 1), randf_range(0.5, 1.5), randf_range(-1, 1)).normalized()
+			child.apply_central_impulse(random_direction * 5.0)
+
+	# 5. Announce the smash (the HUD counts down remaining barrels) and remove the barrel
+	destroyed.emit()
+	queue_free()